The TiC Klunk Killer is made up of two parts - the TiC Rear Diff Mount Bushings, and the Kartboy Rear Subframe Outrigger Bushings. Individually each of these will eliminate the clunk from the rear diff moving around during hard and fast shifts. Together they will considerably tighten up the rear end of the car for a better feel and control with the throttle. Please note that this is the RACE combination and does cause an increase in NVH. These are not for the faint of heart.