The Whiteline Positive Caster Kit for the WRX & STi is designed to improve vehicle stability by adding 0.5 degree static caster to both front wheels. Whiteline’s special, low compliance bushings reduce caster wind-back and maintain tighter tolerances between static and dynamic alignment settings. The additional caster coupled with the firmer bushings serve to dramatically sharpen initial turn-in response, then forcing more consistent alignment angles through the corner due to the reduced bushing compliance