SuperPro 2003 Mitsubishi Lancer Evolution Rear Differential Pinion Mount Bushing Set (w/ AYC)Fits Evo models with Active Yaw Control Only. For models WITHOUT AYC, use SPF1975K This kit replaces the forward differential mount bushings known as the pinion mount bushings. The OEM units are soft rubber and break down fairly quickly with that wear accelerated the harder they are used. The worn bushings allow more movement of the rear differential under changing loads. This can initially be felt behind the wheel as slower and sloppier