I am running an SCT tuner from 5 star tuning. the results are exactly what I was looking for. raise the shift points and hold O/D a bit longer before it downshifted to 3rd. it does firm up the shifts, but nothing that will break anything! it does add power and it is noticeable. I mainly got it for the towing tune with the improved shift strategy. I got mine with 3 tunes....Economy, towing and performance. all 3 do what they are supposed to do. and you can order it with any combination of octane 87, 89, 93. I have the 89 octane tune for all 3.