Ditto on the praise for the Spec. Never heard or seen a complaint. If I hadn't been tight on $ and needed a clutch real bad, the stage three would have been in my garage.

For 500 hp, the Stage 3 is what you need. 450 and under, go with a Stage 2. Of course, what tranny are you running that 500 hp through? Better be something like a Tremec 3550. Much less and you will be breaking frequently. Of course, I should talk, my car still has the original T5.