http://www.measeperformance.com Keith started making 3" dps for hot airs.
ATR has 2.5 up an downpipes, Postons makes good hot air headers, I'm sure they've got more, havent checked their catalog. I'm sure I forgot some other vendors. Theres stuff around, just gotta look for it.
Yeah, ya just gotta look around for the stuff. Get the actual cataloges, ATR's has about 1/2 a page of hot air exhaust parts. I found out about all the different stuff just by reading peoples' profiles an junk.