so i just bought an 04 6.0 with studs, egr delete, AFE stage 2 intake, turbo back and an unknown tune. here lies my dilemma. its faster than my POS cummins ever was, and smokes more too. the folks i bought it from didnt have the tuner, so its stuck on this race tune all the time. id like to be able to switch between mileage towing and race tunes. so the question is if i bought an sct tuner and tried to download new tunes to it, could it screw something up or should i take it to ford and have it reflashed to the factory settings?