Yeah i know i can benifit from a tune now and i may get one once my catback gets here (hopefully nextweek) but to me in a way i think it may be easier to do it at the same time as headers and fans. Yeah i do have 3.73s now but starting to get some noise from them. Shop said the ifs is a pain to work around on these trucks. Ive done the one in my car myaself but that was a 7.5in ring gear and not my dd. I figured if i am getting some wear ill go ahead and bump up to 4.10s and a better locker and yes it is 4x4. What about vette servo thinking about doin that when i put my catback on.