SuperPro Rear Control Arm Upper-Inner & Outer Bushing Kit | 1990 Mazda Miata (SPF1991K)Superpro Rear Control Arm Upper Inner & Outer Bushing Kit 1990 Mazda Miata Part #: SPF1991K Overview The SuperPro Rear Control Arm Upper Inner & Outer Bushing Kit is designed to restore and improve the handling and stability of your 1990 Mazda Miata. Over time, rubber bushings in the control arms can wear out, leading to compromised wheel alignment, increased tire wear, and less precise steering response. This kit provides a direct replacement