Is Deleting L5P Duramax DPF, EGR and CCV Worth It? The Ultimate Kit Guide

The L5P Duramax is the most expensive diesel GM has ever asked you to delete. On a 6.7L Cummins or a 6.7L Powerstroke, you plug a tuner into the OBD-II port and flash. On the L5P, GM encrypted the ECM hard enough that — depending on your year — you’re either buying HP Tuners’ proprietary unlock, or physically shipping your factory computer across the country and parking the truck for a week and a half.

So the question in the title isn’t rhetorical. It’s the exact question a shop owner with a 2017–2023 Silverado or Sierra HD should be asking before they spend anywhere from $2,000 to $9,000 on this job. And the honest answer is: it depends on what you mean by “worth it,” and on which year you own.

What You’re Actually Deleting: Three Systems, One Sticky Problem

A lot of L5P delete discussions stop at “DPF delete.” That’s only a third of the story. The title lists three systems because they share one failure mode: they all feed the intake a steady diet of gunk.

The DPF (Exhaust Side)

The diesel particulate filter is the big canister under the cab. It traps soot, then burns it off during regeneration — dumping raw fuel into the exhaust stroke to spike temperatures high enough to torch the carbon. On a truck that idles, short-trips, or tows heavy, regeneration runs constantly, and the truck is down on fuel economy and up on exhaust gas temperature (EGT) every time it happens.

The EGR (Intake Side)

Exhaust gas recirculation routes hot, soot-laden exhaust back into the intake to lower NOx. The L5P’s EGR cooler is a known leak point — when it cracks, coolant enters the intake and you’re looking at white smoke and, in the worst case, hydro-lock. Even when it’s healthy, it’s feeding abrasive soot into the intake manifold.

The CCV (The One Everyone Forgets)

Crankcase ventilation routes oily blow-by vapor back into the turbo inlet. On its own, EGR soot is dry and powdery. The sticky “black peanut butter” that clogs L5P intake manifolds and MAP sensors only forms when that dry soot mixes with CCV oil vapor. That’s why the CCV belongs in the same conversation.

The point: a real “delete” isn’t one pipe. It’s three systems that all contribute to the same intake-fouling, heat-trapping, regen-triggering mess. That’s the logic behind a complete kit.

The Case For Deleting: What It Actually Fixes

Let’s be precise about what a delete does, because this is where the honest version and the marketing version part ways. A delete doesn’t create power — it removes failure points and restriction. But the reliability benefits are real, concrete, and worth spelling out one system at a time.

1. Deleting the DPF Ends the Regeneration Cycle — And Everything That Comes With It

Regeneration is the single most damaging thing the L5P does to itself. Here’s what stops the day you delete the DPF:

No more post-injection fuel dumps.
To burn soot, the ECM injects raw fuel on the exhaust stroke, spiking exhaust temperatures to 1,000–1,200°F. That fuel isn’t making power — it’s being wasted, which is why fuel economy tanks during every regen. Delete the DPF and that waste disappears.No more heat-cycling the turbo and exhaust valves. 

No more post-injection fuel dumps.
To burn soot, the ECM injects raw fuel on the exhaust stroke, spiking exhaust temperatures to 1,000–1,200°F. That fuel isn’t making power — it’s being wasted, which is why fuel economy tanks during every regen. Delete the DPF and that waste disappears.

No more heat-cycling the turbo and exhaust valves.
Those 1,200°F spikes are hard on the turbo and the exhaust valves. Removing them is the difference between a turbo that lives and one that’s being slowly cooked.

No more ash accumulation.
Soot burns off; ash doesn’t. A high-mileage DPF fills with unburnable ash that no regeneration can remove — it’s a filter on borrowed time, headed for an expensive replacement or cleaning. Delete it and the “ash death clock” stops ticking.

No more backpressure.
The DPF is a restriction in the exhaust path. Removing it lets the VGT turbo spool faster and lowers exhaust gas temperature (EGT) under load — real-world drops of 100–200°F when you’re towing hard.

2. Deleting the EGR Removes the Intake’s Biggest Leak Risk

The EGR cooler is the L5P’s most notorious failure point, and it fails in the worst possible way:

The hydro-lock risk goes to zero.
When an EGR cooler cracks, coolant leaks into the intake, gets pulled into the cylinders, and can hydrolock the engine — a catastrophic, engine-ending failure. A block-off plate plus cooler delete removes that risk permanently.

The intake stops eating abrasive soot.
EGR routes exhaust soot back into the intake, where it fouls the MAP sensor, coats the intake runners, and contributes to the “lazy throttle” that creeps in as miles pile up. Delete it and that contamination source is gone.

The cooling system sheds a load.
The EGR cooler dumps heat into the coolant. Removing it means the cooling system isn’t fighting that extra heat, which matters on a truck that already runs hot under load.

3. Deleting the DEF/SCR Ends the Cold-Weather Failure Chain

The DEF/SCR system rides along with the DPF and brings its own list of ways to strand you:

• DEF heaters that die in cold weather. DEF freezes at 12°F, and the tank heater is a known failure point in northern climates. Delete the SCR and the heater problem becomes moot.

• DEF injectors that crystallize. DEF leaves crystalline deposits that clog the injector over time. Gone with the delete.

• NOx sensors that throw codes. The SCR depends on upstream and downstream NOx sensors that fail and trigger derate messages. Removing the system removes the codes.

• You stop buying DEF fluid entirely. It’s a small recurring cost, but it adds up over the life of the truck.

4. Rerouting the CCV Stops the Other Half of the Sludge

This is the piece most delete discussions miss, and it’s why the title groups CCV with DPF and EGR:

• EGR soot is dry; CCV oil vapor is the glue. The sticky “black peanut butter” that clogs L5P intake manifolds and MAP sensors only forms when dry exhaust soot mixes with oily crankcase vapor. Reroute the CCV so that oil vapor stops entering the turbo inlet, and the sludge has nothing to bind to.

• Cleaner intercooler boots and charge pipes. Oil vapor condenses in the intercooler and boots, leaving the oily residue you find when you pull them apart. Rerouting keeps that oil out of the charge-air path.

The Case Against: The Honest Numbers

Now the part the delete-kit marketing pages leave out.

A Delete Does Not Add Horsepower

The horsepower comes from the tune, not the delete. Remove the DPF, EGR, and CCV on a stock-calibrated truck and you gain essentially nothing at the wheels — the delete just removes restriction and failure points. Every one of those “+150 hp” claims is the tune doing the work, and you could get a meaningful chunk of that tune’s power even with the emissions hardware still on the truck.

That’s not a knock on deleting. It’s a recalibration: you delete for reliability and intake cleanliness, not for power. If power is your goal, the tune is the thing you’re actually paying for.

The Tune Is Where the Power Lives (And What It Actually Adds)

So if the delete adds no power, where do all those “+150 hp” promises come from? The tune — and the tune genuinely does add a lot. Here’s the stock rating stacked against two common tune levels:

• Stock: 445 hp / 910 lb-ft — the factory crank rating for the 2017–2023 L5P.
• Mild tune (+75 hp / +150 lb-ft): roughly 520 hp / 1,060 lb-ft — the safety sweet spot for a truck that still tows and daily-drives.
• Hot tune (+150 hp / +300 lb-ft): roughly 595 hp / 1,210 lb-ft — already past the Allison’s ~500 wheel-horsepower ceiling.

Two things matter more than the headline numbers:

1. The power comes from the tune, not the delete. You can get a large chunk of that gain with the emissions hardware still on the truck — emissions-intact tunes reach 500+ hp. So “deleting for horsepower” is a false premise; the tune is what you’re actually paying for either way.

2. Horsepower is not free. Every extra pony pushes the transmission (a ~500 whp limit), the head gaskets, and the pistons harder. Running a hot tune without a transmission tune is “playing with fire” — the two most common results being a blown head gasket or a blown transmission.

The lesson isn’t “don’t tune.” It’s that the tune is the part that matters, and it’s the part you have to respect. A delete without a tune does almost nothing for power; a hot tune without supporting transmission work is a liability. Get both right, and the mild-tune sweet spot is where the L5P actually shines.

The Real All-In Cost Is Higher Than the Pipe

An L5P delete is not a $400 pipe job. Here’s what a complete 2020+ build actually costs, line by line:

Line Item	Cost
HP Tuners modified ECM (or E41 unlock)	$1,800
Core charge (if you keep your factory ECM)	$625
MPVI2 device	~$300
HP Tuner TUNING FILE + 6 Credits (TruckTok)	$1,300
DPF/CCV/EGR Delete & Downpipe w/Can Bus kit (TruckTok)	$230–$1,532
Subtotal (parts + tuning only)	~$4,255–$5,557

That’s before labor — shops quote around $2,000 for the install, pushing a turnkey 2020+ delete toward $7,500. 

It’s Illegal on Public Roads

Removing or tampering with emissions controls violates the federal Clean Air Act (42 U.S.C. § 7522), with civil penalties for individuals up to $5,911. Kits are sold for off-road, race, or competition use only. Warranty coverage on the emissions and powertrain systems is gone. This isn’t a footnote; it’s the single biggest “con” in the whole analysis.

Know Your Generation: 2017–2019 vs 2020+ Is Not a Footnote

The L5P spans two meaningfully different eras, and mixing them up is the fastest way to buy a box of parts you can’t use.

2017–2019: The “Figured Out” Years

• ECM: E41 controller. OBD-II tunable through HP Tuners’ MPVI platform — no physical ECM swap required.

• Transmission: 6-speed Allison 1000, with mature TCM tuning support.

• Maturity: Owners and installers call these trucks “100% figured out.” Install errors aside, a proper 2017–2019 delete is a known, repeatable job.

2020–2023: The “Bring a Backup Vehicle” Years

• ECM: Same E41 family, but encrypted hard — you swap the factory ECM for an HP Tuners unit, or send yours out. Video builders report 11 days of downtime just waiting on the ECM.

• Transmission: 10-speed Allison 10L1000. The T93 TCM wasn’t cracked at the time of writing, meaning no aftermarket transmission tuning on 2020+ — a real problem, because…

• The trap: the 10-speed can only hold around 500 wheel horsepower, and a tuned L5P clears that easily. No TCM tune = slipping clutches and a transmission you can cook if you run a hot tune hard.

2024–2025 (E42): The Next Cliff

GM moved to the Global B E42 controller. These require mailing the factory ECM to HP Tuners for a physical unlock (roughly $999.99 and 7+ days), and HP Tuners only accepts the original ECM — a spare won’t do. Worth knowing so you don’t buy a 2017–2023 kit for a 2024 truck.

The CAN-BUS plugs are generation-specific too — 2017–2019 and 2020–2023 use different connector sets. This is exactly the kind of detail a modular kit has to get right, or you’ll be fighting ghost codes and corrosion in orphaned harnesses.

How to Choose a Quality Delete Kit

The gap between a good L5P delete kit and a cheap one isn’t the pipe diameter — it’s the details that determine whether the job goes smooth or turns into a weekend of chasing leaks and ghost codes.

1. It’s Modular, Not One-Size-Fits-All

The L5P spans two eras with different ECMs, transmissions, and — critically — different CAN-BUS connectors. A quality kit lets you pick the intake-side parts (EGR and/or CCV) and the exhaust option. A kit that sells you “fits 2017–2023” as a single rigid bundle is betting that a 2017 and a 2023 truck are the same. They’re not.

2. The Coolant Reroute Is Complete

The single most common kit deficiency is a half-baked coolant solution. Removing the EGR cooler and the turbo’s emissions plumbing means rerouting several coolant lines — and the routing differs between 2017–2019 and 2020+. A quality kit includes the block-off plugs, the reroute hoses or fittings, and clear instructions for your year. 

3. The CAN-BUS Plugs Are Matched to Your Year

When you remove the emissions sensors, you leave orphaned harness connectors exposed to water, salt, and corrosion — which eventually shorts a 5V circuit and takes down unrelated sensors. A quality kit includes year-specific CAN-BUS plugs (2017–2019 vs 2020–2023) to seal those connectors. If a kit doesn’t even mention CAN-BUS, it’s incomplete for an L5P.

4. It Includes the Downpipe (Or Lets You Add It)

Many “DPF delete” kits stop at the pipe and leave the restrictive factory downpipe in place. The L5P’s stock downpipe has a tight bend right off the turbo, and it’s where the SCR lives on a 2020+. A quality kit either includes the 3.5" downpipe or makes it a clean add-on — because leaving the factory downpipe in place means you’re leaving the SCR and a real restriction in the system.

5. The Fitment Statement Is Honest

A quality kit tells you what it doesn’t fit. The ER-0290 explicitly excludes Cab & Chassis commercial trucks, because the exhaust routing is different. A kit that just says “fits L5P Duramax” without breaking out year, cab, and chassis is asking you to find out the hard way.

6. Material and Construction Are Stated, Not Guessed

Mandrel-bent piping (not crush-bent), proper stainless or coated steel, and real gaskets instead of “use your old ones” — these are the signs of a kit built to last. If the listing won’t tell you the material or the bend method, assume it’s hiding something.

The short version: a quality L5P kit is modular, year-matched, and honest about fitment — it treats DPF, EGR, CCV, downpipe, and CAN-BUS as one coordinated job, and it gives you the instructions to back it up. That’s what the “Ultimate Kit” in the title actually means.

2017-2023 6.6L Duramax L5P DPF/CCV/EGR Delete & Downpipe w/Can Bus kit

This is where the “Ultimate Kit Guide” part earns its name. Rather than piecing together a downpipe from one brand, an EGR kit from another, and a CCV reroute from a third — then hoping the CAN-BUS plugs match your year — the 2017–2023 L5P DPF/CCV/EGR Delete & Downpipe kit bundles the whole job into one configurable order.

Fitment: 2017–2023 Chevrolet Silverado HD and GMC Sierra HD 2500/3500 with the 6.6L L5P Duramax. Does not fit Cab & Chassis commercial trucks.

The kit is modular, so you pick the pieces that match your truck and your goals instead of paying for what you don’t need:

• Intake side (choose one or both): the EGR valve & cooler delete (block-off plates + coolant reroute) and the CCV reroute/delete (keeps oily blow-by out of the turbo inlet). Taking both is what actually stops the intake sludge, per the “dry soot + oil vapor” mechanism above.

• Exhaust side: a 3.5" downpipe (removes the restrictive bend right off the turbo), plus your choice of a 4" DPF race pipe (replaces just the DPF/catalyst section) or a 4" or 5" downpipe-back system (full turbo-back replacement). Add a muffler if you want the tone without the straight-pipe drone.

• Electrical side: CAN-BUS plugs matched to your year — 2017–2019 or 2020–2023 — to seal the orphaned sensor connectors against water and corrosion.

Because it’s one kit with 84 configurations, the price spans $230 (downpipe only, for someone doing a partial build) up to $1,531.99 (the full triple-delete with 5" downpipe-back exhaust, muffler, and CAN-BUS plugs). A complete EGR + CCV + 4" race pipe + downpipe + plugs setup lands right around $950, which is a genuine value against buying each component separately from different vendors.

The Install: Tune First, Then Unbolt

The install is a full weekend job — experienced builders put it at 35–40 hours solo on a 2020+. The sequence matters more than the wrench sizes, and there’s one rule above all others.

Step 0: Tune Before You Touch a Bolt

Flash the delete tune into the ECM before removing any hardware. On a 2017–2019 that’s an OBD-II flash; on a 2020+ that means having the swapped/unlocked ECM back in the truck and the tune loaded first. Skip this and the truck throws a wall of codes and drops into limp mode. One 2024 builder learned this the hard way — he pulled the exhaust while waiting on his ECM, only to reinstall it all to plug the sensors back in and clear the codes.

Tools You’ll Want

• Socket set with 10mm, 13mm, 15mm, 22mm, plus a deep 11mm for the charge pipe
• 3/8" ratchet with an 18" extension and an 11/16" deep wheel for breaking tight bolts loose
• Swivel sockets, open-end wrenches, pry bar, flathead screwdriver
• Sawzall for cutting the factory exhaust out in sections
• Vice grips and a coolant catch pan (for the DEF injector’s coolant lines)
• Dielectric grease, zip ties, and a roll of 5/8" heater hose (see the coolant note below)
• Torque wrench, magnetic tray (the small bolts love to fall into the engine valley)
• Gloves for the downpipe heat wrap — it’s fiberglass and it itches

Phase 1: Get the Factory Exhaust Out

1. Tune first (Step 0, non-negotiable).
2. Disconnect both battery negatives, then drain the coolant at the passenger-side radiator drain plug.
3. Remove the airbox, intake piping, and heat shield to open up the engine bay.
4. Cut the exhaust out in sections. The factory system is one big piece; on a full 5" job, builders cut it at the axle, at the canisters, and behind the SCR with a sawzall rather than fight it over the crossmembers. Spray the hangers with lubricant and pry them off.
5. Unplug every sensor as you go and label them — the DEF injector up front has two coolant lines (clamp them with vice grips before cutting), and there’s a sensor connector tucked up on the frame rail.

Phase 2: Remove the EGR and the Intake Bridge

6. Remove the AC compressor (four bolts; the rear one needs an open-end wrench and a pry bar on the fan shroud) and the alternator (release the tensioner, pull the belt).
7. Remove the intake horn and the Y-bridge — eight 10mm bolts, with the bridge lifting out after you swing the harness and the coolant hardline clear. Stuff rags into the open intake runners.
8. Remove the EGR cooler (five 13mm bolts) and the lower EGR valve (four 13mm bolts), then install the block-off plates with fresh gaskets. Torque the lower EGR valve block-off to 25 ft-lbs.
9. Reroute the coolant lines. This is where the years diverge — the 2017–2019 and 2020+ trucks route the turbo coolant return and the EGR coolant feed differently. A kit’s supplied hose is sometimes too short (a known Diesel Dudes complaint), so keep 5/8" heater hose on hand and cut to fit.

Phase 3: Turbo, SCR, and Downpipe

10. On a 2020+, the SCR sits behind the turbo, so you’re pulling the turbo to get at it. Remove the heat shields, the NOx sensor (a 22mm socket after cutting the sensor free), and the V-band clamps on both the turbo outlet and the downpipe.
11. Disconnect the turbo oil drain line (two bolts), the coolant feed/return lines, and the four 15mm bolts holding the turbo to the pedestal. Note which bolts are long vs short — mixing them up strips the holes.
12. Pull the turbo, then the SCR. You’ll almost always find a mouse nest in the valley — clean it out.
13. Install the 3.5" downpipe from the top (wrap it in heat wrap first, wearing gloves), then set the turbo back on with a fresh pedestal gasket. Torque the four turbo bolts to 43 ft-lbs and the oil drain line to 89 in-lbs.
14. Reconnect the coolant lines, the intake bridge, and the harness. The throttle valve stays unplugged — don’t reconnect it.

Phase 4: CCV, CAN-BUS Plugs, and Finish

15. Install the CCV reroute while the intake side is apart — it bolts to the back of the turbo and the PCV block, redirecting oil vapor away from the compressor inlet.
16. Install the CAN-BUS plugs last, matched to your year (2017–2019 or 2020–2023). They’re usually three connectors — one at the SCR NOx sensor, one on the passenger frame rail, one on the DEF harness. Add dielectric grease, seal them, and zip-tie them out of the way. Skipping this step leaves the harness connectors open to water and corrosion.
17. Refill the coolant, reconnect the batteries, start the truck, and check for leaks in the turbo valley and underneath. Top off the coolant after a short drive — you’ll usually need to add more once it cycles.

The Three Mistakes That Bite People

• Not tuning first — instant limp mode and a wall of codes.
• Mixing up the coolant lines on a 2020+ — the turbo’s coolant return reroutes to the reservoir, and getting it wrong means air pockets and overheating.
• Forgetting the CAN-BUS plugs — the truck won’t run right, and exposed connectors corrode.

Take photos of every connector before you unplug it. The reinstall is the hard part; the photos are what make it go back together.

What a Delete Won’t Fix

Here’s the honesty check that separates a good decision from a $9,000 disappointment. A delete does not fix:

• The transmission limit. The Allison 1000 (6-speed) and 10L1000 (10-speed) hold roughly 500 wheel horsepower. A hot tune will outrun the transmission — and on 2020+ trucks there’s no TCM tune yet to paper over it. A built transmission is another $5,000.
• The MAP sensor fouling. This is actually a symptom the delete does help — less soot means less MAP clogging — but a dirty MAP sensor is a separate maintenance item, not something the delete makes go away overnight.
• The #4 injector connector. A known L5P weak point that throws P0204 and limp mode. Nothing to do with emissions — a delete won’t touch it.
• The DEF heater. Delete the SCR and the DEF heater becomes moot, but on a stock truck it’s a cold-climate failure point that has nothing to do with whether you delete.
• Your driving habits. If the truck idles for hours, tows heavy, or lives in short-trip duty, a delete removes the symptoms (regen, EGT, sludge) but the duty cycle itself is still hard on the engine.

The Verdict: When It’s Actually Worth It

So, back to the title. Here’s the decision made plain.

A delete is worth it if:

• You plan to keep the truck long-term and don’t care about resale.
• The truck works hard — idles, tows, short-trips — and regeneration is a constant, fuel-wasting annoyance.
• You’ve already had, or want to avoid, an EGR cooler leak or DEF system failure.
• You own a 2017–2019 and want the most mature, well-trodden delete path.
• You understand you’re doing this for reliability and a clean intake, not for horsepower.

A delete is probably not worth it if:

• You’re chasing power — the tune is what makes power, and you can tune an emissions-intact truck for a meaningful chunk of it.
• You might sell or trade the truck in the next few years — you’ll get none of the money back.
• You own a 2020+ and aren’t prepared for the ECM-swap cost, the two-week downtime, and the missing TCM tuning.
• The truck is a daily driver in an emissions-inspection state — the legal risk is real and the fine is on you.

The through-line: delete the L5P for the right reason. Do it to stop the regen cycle, remove three chronic failure points, and keep the intake clean for the long haul — and do it with a kit that treats DPF, EGR, and CCV as one job instead of three separate afterthoughts.

Conclusion

For the complete 2017–2023 L5P delete solution — DPF, EGR, CCV, downpipe, and year-matched CAN-BUS plugs in a single configurable kit — head to TruckTok.com. The ER-0290 kit is built specifically for the Silverado HD and Sierra HD L5P, with fitment guidance for your exact year and cab configuration, and every option ships free. Build the kit that matches your truck, not a one-size-fits-all pipe that leaves the other two systems still gumming up your intake.

Frequently Asked Questions

Q1: Does deleting the L5P add horsepower? 

A: No — the delete removes restriction and failure points, but the power comes from the tune you pair with it. A delete alone gains essentially nothing at the wheels. If power is the goal, the tune is the part doing the work.

Q2: Do I really need to delete the EGR and CCV along with the DPF? 

A: If your goal is a clean intake and long-term reliability, yes. EGR feeds dry soot while CCV feeds oil vapor, and the sticky sludge only forms when they mix. Deleting the DPF alone leaves that fouling problem intact.

Q3: How much does a complete L5P delete cost all-in? 

A: Around $6,200–$6,800 in parts and tuning for a 2020+ truck (ECM, credits, device, tune, hardware, exhaust, plugs), plus roughly $2,000 in labor. A 2017–2019 is cheaper since it doesn’t need the ECM swap.

Q4: What’s the difference between 2017–2019 and 2020–2023 for deleting? 

A: The 2017–2019 uses an OBD-II-tunable E41 ECM and a 6-speed Allison with mature TCM support. The 2020–2023 needs an ECM swap/unlock and runs a 10-speed Allison whose TCM wasn’t cracked at the time of writing.

Q5: Why do I need CAN-BUS plugs? 

A: When you remove the emissions sensors, their harness connectors are left exposed. The plugs seal those orphaned connectors against water and corrosion, and they’re matched to your year range (2017–2019 vs 2020–2023).

Q6: Is an L5P delete legal? 

A: No for on-road use. Removing emissions controls violates the federal Clean Air Act (42 U.S.C. § 7522) with civil penalties up to $5,911 for individuals. Kits are for off-road, race, or competition use only.

Q7: Will deleting void my warranty? 

A: Yes — removing emissions hardware and running a non-stock calibration will void the emissions and powertrain warranty coverage on the affected systems.

Q8: Will a delete hurt my resale value? 

A: Almost certainly. Dealers in many states won’t take a deleted truck on trade, lenders may balk, and you’ll get none of the $6,000–$9,000 back. It’s a keep-it-forever decision.

Q9: Why is the L5P so much more expensive to delete than other diesels? 

A: GM encrypted the ECM, so 2020+ trucks need an HP Tuners unlock or a physical ECM swap — a cost other platforms don’t have. The L5P also requires year-specific CAN-BUS plugs and has a unique turbo-and-SCR layout that makes the install longer.

Q10: Is the downpipe worth doing on its own? 

A: The factory L5P downpipe has restrictive bends right off the turbo, so a 3.5" downpipe helps spool and lowers EGT even on a partial build. It’s the cheapest meaningful upgrade in the kit, and you can start there and expand later.