Solid as a rock, the PERRIN Performance Master Cylinder Support quickly solves a long-time Subaru braking issue: flexing of the firewall under hard braking. Crafted from 6061 aluminum, Perrin's adjustable Master Cylinder Support bolts from the brake master cylinder to the driver-side shock tower to fix the problem and deliver firmness to the pedal.
Like most cars, the brake master cylinder and brake booster all bolt to the fire wall. In most cars it not a noticeable thing, but the firewall flexes when the brakes are applied. The harder you push the more it flexes. The PERRIN Master Cylinder Stiffi keeps the firewall from flexing by using the shock tower to brace against as the wall starts to flex. This simple device is a noticeable improvement, similar to upgrading to Stainless Steel Braided Brake lines.