Lets talk about the things that you need to consider when deciding to upgrade your WRX or STi’s braking performance. The first thing to discuss is brake fade. There are two main causes of brake fade:

1) Overheated (boiled) brake fluid

2) Pad material failure

Brake fluid overheats when the calipers and the brake pads transfer excessive heat into the fluid causing it to boil. Boiled brake fluid changes to compressible vapor which causes the spongy pedal you feel with hot brakes. The other type is caused by the overheating of the pad material. The surface of the pad at the rotor contact face turns to a liquid and lowers the coefficient of friction rather drastically. This is caused by using the wrong pad compound for the application, or not bedding the pads properly and experiencing the phenomenon known as "green fade". We will discuss this when we talk about brake pads.

There are several parts of the overall braking system that can be upgraded individually; other components require installation as matched parts.

In this order, you should consider:

1) High-Performance Brake Fluid

2) High-Performance Brake Pads

3) Larger Rotors and Calipers

4) Master Cylinders (when appropriate)