This dual purpose adjustable aluminum differential (diff) mount bushing for  BMW E30,  E36 318ti, Z3 can be used n either a centered or offset  position. The stock rubber diff bushing deflects as torque moves through the drivetrain, which allows the differential to move.  Upgrading your stock rubber diff bushing to AKG's aluminum differential mount bushing will eliminate all differential movement for increased power transfer to the rear wheels.  The material used for the diff mount bushing location(s)  must match the material used for the subframe bushings. Although solid aluminum bushings are the hardest available and have a longer life span than other bushings, they are also extremely harsh and unforgiving on the chassis. Cracks may occur around the mount. Any area using aluminum bushings should be reinforced and consistently checked before/after each race. Made of solid CNC'd 6061- T6 aluminum. Engineered for a perfect fit. Recommended Use:  RACE / TRACK NVH Increase: High Designed for the following models: BMW E30 (1984-1991)   318, 323, 325, M3 BMW E36 (1992-1999) 318ti ONLY BMW Z3 (1996-2002) 2.3, 2.5, 2.8, M Made in USA