2011 Colorado 5.3 V8
Seems to work well. It is still a little early to be able to tell. Instalation was easy. I could tell a difference between the different types of tunes. The milage that I was getting on the highway was terrific to start with and I haven't had a chance to go on a road trip since changing the tune. Around town it is so hard to tell because of all the various conditions.
Wanted a little more HP...and got it!!!
I used this programmer in my Coly, 3.7 i5 because I have a 19'Hybrid Travel Trailer that I pull. I filled the tank with 93 Octane and in comparison w/o the programmer...Quite a significant difference. Not quite sure what I got for mileage but for HP there was a noticeable difference. I also installed a K & N Cold Air Intake so as a team, I let out a few more ponies. So far, so Happy!!