The Cusco Brake Cylinder Stopper is designed to reduce the unwanted flex of the brake master cylinder when the brakes are applied. Limiting this movement means that more of the force that you apply to the brake pedal is directly applied to the brake calipers, substantially improving pedal feel.
This works well paired with Stainless Steel Brake Lines.
This part fits the 2002 - 2007 Subaru WRX and STi.
Cusco Part # -- 666561ALHD
Please note that the car pictured above is right-hand drive, and that your part will be the same item designed for the left hand drive vehicles.