They use an organic friction disc to retain drive-ability similar to standard

The Turbosmart RacePort is famous for being an amazingly small and light BOV for turbocharged competition level engines

Wisefab's upper control arm for the BMW E36 and E46

For maximum adjustment range check out the upper control arm  aswell

Replacement Diaphragm for Power Port BOV

Clutch Kit - Xtreme Performance Heavy Duty Sprung Ceramic 320Nm KMG22002-1B JR32 They use an organic frictionXtreme Performance sprung ceramic kit 1B Recommended for: Motorsport ApplicationsThese kits are available with sprung ceramic friction discs and are designed for motorsport applications where higher heat and torque capacity is required. These can also be used in some road applications. Specifications: Torque capacity 320Nm Clamp load Increased over standard Sprung Ceramic Friction Disc Heavy Duty Pressure Plate Kit contains everything you need for a