i know for clutches. exedy's stage 1 disc, is like most others stage2, being a organic type full disc. then exedys stage 2 disc, is a 3 puck cerametallic type, while others stage 3 would be a 6 puck design of the similar material. but that's for clutches. but not all manufacturers go by a certain, stage, this, is always, that. as far as turbos. i'm clueless. lol