I have had this tune on my 2013 Chevy Malibu for several weeks now. All I can say is WOW!!! This tune and transmission tune is outstanding. You literally have to retrain yourself on how to drive the car because it is so responsive now. I love it and it's so much faster now. I do have the K&N CAI for this car installed but stock exhaust. I run 93 octane. The car is so much more fun to drive now...it is hard to explain unless you have a Malibu and then install the tune and drive it. You will experience an incredible change and it will put a huge smile on your face!