I Was little skeptical at first, but I love it.
I bought one of the plug in ones and was a little skeptical at first, but I love it. I always pass people going the speed limit and when you're in 4 cylinder mode behind the car and try to punch it a little or more my system would have a hard shift in the transmission or whatever it was. I just didn't like it, i felt it was doing damage to my power train. And I only have 75k on my 2011. You can tell right away when you start up the exhaust even sounded nicer. No more sluggish engine anymore, and who cares if you might lose 1 to 2 mpg. I know I don't. I also like that you can use it on different years and models.