Originally posted by RS*R This D1 Spec kit replaces key components such as the front strut rod bushings, front and rear control arm bushings, and front and rear sway bar bushings, but RS-R felt that there should be more to this kit then to just improve these suspension components and took this kit to the next step. To supply the performance enthusiast with their high needs of drifting and road racing, RS-R felt the next step to improve the cars performance is to include polyurethane bushings that replaced the rack and pinion bushings, and rear subframe mount inserts. The rack and pinion bushings improve the response of the steering response from the steering wheel to the front tires. While the rear subframe inserts improves the response of the entire rear suspension by minimizing the play from the rear subframe.