I have a 07 gmc slt new body style with the 5.3. I have added 22'' wheels and the speedo is off. So I was thinking about getting a programmer to help with shift points, mph vs tire size change for proper mph. And didnt know if I could help out with the mpgs with a programmer also? Any Ideas on brands, prices, and what wont hurt the truck? Right now it only has 60k miles and is no longer under warranty.