This kit assumes coilovers

and Yellow Spring rated to -22 to -20 InHg (installed)

an O-ring is not needed to create an effective seal

Compressor Inducer: 78mm

Clutch Kit - Xtreme Performance Heavy Duty Cushioned Ceramic 830Kg 540Nm KSU23012-1C JR43 This kit assumes coiloversXtreme Performance Cushioned Ceramic kit 1C Recommended for: Motorsport ApplicationsThese kits are available with cushioned 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 540Nm Clamp load 830Kg Increased over standard Cushioned Ceramic Friction Disc Heavy Duty Pressure Plate Kit contains everything