Originally designed for about 100 horsepower, the 6 bolt flywheel interface on the VW / Audi engines struggles when subjected to serious power. Even with ARP Flywheel bolts, this interface can become taxed and allow the flywheel to slip around under high torque. This leads to wear between the surfaces, and shortly thereafter complete failure of the bolts and joint. This ruins the flywheel and crankshaft, and can even damage the transmission bell housing. In order to fight this we had EKagrip make some of their patented nickel and diamond coated friction shims. These shims increase the friction between the two components by up to 3 times what is seen with regular steel on steel contact. This greatly increases the load which can be carried. The shims are .008" thick, and do not cause any alignment problems with the clutch / flywheel. An absolute must for any engine making 450+ ft-lb with the 6 bolt VW/Audi flywheel flange. Increases friction by up to 300% Fits all VW/Audi 6 bolt flywheels A must for high HP engines