I bought a tuner direct from 5 star that came with custom tunes plus I added one of my own for E-85. I have a cold air intake and magnaflow cat back system. Plus my truck is a flex fuel so it comes with larger factory injectors. Running E-85 with the custom tune is amazing. I can smoke up my 285/55/20 Goodyear ultra terrains no problem. The throttle response is much better and the transmission shifts are a lot firmer. I didn’t loose any fuel mileage, in fact I gained mileage on the highway. The guys at 5 star are great and the tuner works great.