I don't care what anybody says, a t5's gonna shatter like a glass house behind the abuse of slicks and a 500 horse engine, ESPECIALLY if you use a hard slamming spec clutch. I'd like to suggest a tremec or gforce trans, and NOT a spec, something that's a little softer. I'd like to suggest mc leod, but I have no personal experience, nor a car with that kind of power, just do your homework properly on this, or you're gonna have a really large repair bill.