The Whiteline Positive Caster Kit for the 02-07 WRX & 04-07 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.

Whiteline's "Race" version of the Positive Caster Kit incorporates a firmer bushing, that is black in color, for further reduced deflection.The "Race" version is not recommended for street use due to the increased noise and harshness.

Finally, the "Race" version incorporates a metal bearing for the least amount of deflection as possible and adds 1/3 of a degree of caster.The "Race" version is not recommended for street use due to the increased noise and harshness. All three of these kits will add 0.5 degrees of caster.