Heavy duty pressure plate, sprung or solid, with 4- or 6-pucked ceramic disc. This makes for quick engagement along with tremendous holding power. If your BMW has major upgrades and is making loads of power, the FX400 clutch is for you - especially if your BMW is a dedicated track car. You will experience harsh engagement that is not suggested for daily driven cars, but is ideal for the for the aggressively driven weekend toy and track driven 135/335. Clutch Masters offers the FX400 as a 4-puck or a 6-puck kit. The 6-puck kit will dissipate heat better than the 4-puck version, but the 4-puck can handle a little bit more power.