The stock bushings in the front lower control arm on current Subaru models is one of the weakest points of their suspension design. This lower control arm rides on a large round bushing at the rear, which provides most of the support for the lower control arm. The OEM bushing was designed primarily for comfort and is very soft. It's known to fail prematurely, especially in areas with poor roads. When your front tyres encounter a bump in the road, especially while cornering, the softness of this bushing allows for very large toe changes in the front independent suspension.
You may have noticed that you have to constantly correct the steering mid corner - this is the reason why. When you hit a bump, the front suspension responds to the impact by pushing the lower control arm backwards and up. Due to the independent design of the front suspension, this leads to the front tyres having different toe angles while responding to that bump. This also places a lot of pressure on the rear bushing, which is why our design incorporates a lip at the top to keep it from popping out of the lower control arm. These bushings replace the large rear bushing on the control arm, firming it up without adding too much NVH. These bushings come in two flavors, +0.05 offset and standard. The offset Caster Adjustment Bushing system does just that, increases the caster. The additional caster improves turn in when cornering, plus improves straight line stability.