Differential bore calipers can help improve your brake calipers. As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons, the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back. Shop our brake performance part systems for your Porsche 991 GT3 (2014+).