Longtubes will fit with the awd t-case no problem, as long as you go with the ones that fit a 4wd truck. I think some of the cheaper long tubes need modifications to the y-pipe to fit a 4wd though. I was planning on running American Racing Headers on mine as I've heard nothing but good things about them, the full header and y-pipe system without cats runs close to 1400 though so its quite pricey