A byproduct of the PSRS kit is that it reduces some of the built in "anti-lift" that Subaru builds into the suspension geometry. Changing the geometry toward a Pro-Lift setup which means there is more weight transfer happening under acceleration and deceleration. During acceleration this helps transfer weight to the rear of the car creating additional traction for the front tires, which reduces understeer. Same thing happens under braking.

The bushing in the PSRS is purposely offset from center-line. This adds approximately 0.5 degrees of caster to the front suspension. Caster is the angle on which the steering knuckle rotates. Adding caster makes the car turn in faster by providing a larger contact patch as the wheels turn on the steering axis.