SPL Parts 15-21 Ford Mustang S550 Rear Toe Arm BushingS550 Mustang Rear Toe Arm bushings replace the mushy factory bushing in the rear knuckle. This replacement bushing removes the large amount of deflection that the toe bushing sees under heavy load. For reasons unknown, the Ford Performance replacement bushing for this location is wider than the regular Ford bushing, not allowing our Toe Arm, which was designed for the OEM knuckle, to fit over the Ford Performance bushing. If you plan on upgrading your