Where are you getting your tuner from and what is the cost? From the research I have done I think you have to get a custom tune to disable the rear O2 sensors, what other benefit is there to a custom tune? Right now my only performance mods will be headers and some sort of cold air intake. I'm wondering what benefits a custom tune will give me over the canned tunes. I have thought about just installing some high flow cats so I don't have to worry about the O2 sensors, but I'm guessing there may be other issues I'll run into.