The ALOY0046XK Caster increase kit will deliver extra caster to enhance the handling and directional stability of the vehicle. Designed to reduce Arm movement, this kit comes with LH and RH lightweight alloy arms, heavy duty M-Spec ball-joints, brackets and SuperPro Polyurethane bushes. It is a complete changeover kit for your BMW E46 and E85/E86 Z4. The complete arm kit is fitted with SuperPro bushings to positively locate the rear of the arm and eliminate the unwanted flex that comes with the O.E rubber bushing. SuperPro has the best solution for your BMW!