The programmer got my speedometer corrected and I didn't change anything with my transmission. When I get a few more miles on it I'll be able to see if my MPG has improved. The only issue I had was when it was first hooked up it let me know that the programmer had to be updated and the information downloaded to it. Once that was done I was able to program my truck.
The Hypertech MaxEnergy Programmer is awesome! Easy to use, very intuitive user interface, and although I'm using the Regular fuel tuning, the change in HP is noticeable from the beginning. The only inconvenience I ran into was that the speedometer adjustment was not very precise, I have 33" tires, but after several attempts I had to end up specifying 31.5" tires on the programmer in order to get the speedometer to be accurate, and every time I had to reprogram the entire thing which was a bit time consuming. Other than that little inconvenience, it is a great product!