Honestly I haven't driven it enough to notice subtle differences, but like I said I did notice that it pulls harder and the pedal is a lot more responsive. At highway speeds to pass, you may simply be right at the edge where you should be in 3rd gear for acceleration but the car keeps you in 4th. I haven't got a chance to test that kind of stuff yet, but I can tell you that I did notice quite a difference in the before and after and I would say it was worth the money. I would assume the results would be the same if not better than the PCM you got from the dealer, seeing as how they tune these engines pretty frequently and I'm sure they know how to make it drive better than the dealer knows how to