Brock's 2005 GSX-R1000: S1005-CM-Ultra Clutch Mod Kit includes a CNC machined Billet Aluminum and Hard anodized  one piece replacement for the stock two piece back torque limiter. This represents a nearly 70% decrease in rotating mass in this area alone. We also include an ultra light and coated clutch pack shim spacer to increase spring pressure using the stock clutch springs. We elected to shim the entire clutch pack as opposed to the springs as the minimal thickness required created problems under the spring retaining screw heads. The current clutch lifter pins and nuts located in the pressure plate are also no longer required. No core required.