The HKS Kansai Service (FRP) Rear Diffuser improves undercarriage aerodynamics, and also improves rear downforce, without introducing aerodynamic drag.

Improving the aerodynamics underneath the car can reduce the coefficient of drag, which increases top speed.

Fits: 2002 - 2006 Subaru Impreza WRX STi may need modification for US Spec Bumpers.