What kind are you looking for? If you look in the right places it shouldn't be hard to find just about any of the major brands. Most of those big sites only carry a couple brands, so you don't get a lot of selection for less commonly modified machines like a warrior. But there's tons of them out there. DMC Alien, HMF, Pro Circuit, Big Gun, Yoshimura, Supertrapp, White Brothers, FMF, DG, and I think GYT-R, and PRO-Y all make exhausts for the Warrior, and i'm sure there are others as well. If you have one in mind specificially and can't find it yourself, post it up and somebody here should be able to find one for you.