Running 3" Duel Ex with headers. Going to be buying a bigger air cleaner as well hearing it could help a bit. Eventually I'll be taking off the rear-end and again watching videos how to Remove current gears(3.43) and put 3.73 posi. Not sure if limited slip or full posi locker is a better option. I'm shooting for speed over gas mileage though as well. Not worried bout 5mpg long as the Hp match's my gas consumption .