In know I know I will get a custome tune later! After cam and headers etc. Got a screaming deal on a predator tuner for my 01 6.0l hd 4x4 though. So im gonna use it. My question is has anyone run there performance tune with low grade fuel? Or can you run the 89 tune and also turn off torquemanagment and mod some other things at the same time. I know this is kinda a newbie question!! Just looking for some advice. I do tow an 18" trailer and bikes etc. Thanks agian. It has CAI and Cat back etc