I had an act street disc and pressure plate on my KA, and an Xtreme disc and pressure plate on my first SR. The Xtreme was slighty annoying driving in traffic but was awesome for drifting. The Street setup was way easier to daily, and had really good bite. Even with all the clutch kicks, it never slipped (but I wouldn't buy it again, I wanted a heavier pedal feel). On my latest setup I went with Exedy Stage 2 (3puck), its got awesome pedal feel, but I haven't driven my damn car yet!! But it was fucking expensive, I think I paid almost 400 dollars for it. S15 clutches are money, and hard to find in the US.