The Girodisc system is a direct replacement for the OE disc. No modifications are necessary. The disc will bolt directly to the car and work with OE calipers perfectly. By upgrading your brakes with lightweight high performance replacements as opposed to a big brake kit, your factory bias is maintained as well as your ABS efficiency. The Girodisc front rotors are approx 16. 5lbs vs. 20. 5lbs for the stock units. This reduction in rotational and unsprung weight allows for quicker acceleration and suspension response. The central hat section of the disc is made from 6061-T6 aircraft specification aluminum. The disc is made from cast iron to the same specification and material as used by professional racing organizations. It is a curved vane design, developed in racing to act as a centrifugal pump to force cooling air through the disc. The rotor and hat have a floating mount system, which utilizes 10 high strength alloy steel drive pins, manufactured by Girodisc to our own specifications and cadmium plated for a long lasting corrosion resistance. These pins take the load from braking actions while maintaining the axial and radial float between the hat and disc. In order to keep the rotors from making noise when cold, the pins are mounted with anti-noise spring washers on the rotor side which allow the rotor to grow with heat expansion but eliminate the rattle and noise associated with floating rotors. This float also allows the rotor to self center between the pads. Once the Girodisc system is in place, simply replace the cast iron rotor when needed. When used with performance pads and hi-temp fluid, you have what amounts to a truly amazing solution to overheating or warping rotors. Sold/priced in pairs.