StopTech Floating Rotor Replacement, Zeckhausen Racing StopTech 2 Piece AeroRotor Slotted 326mm x 30mm 2003 2015 Subaru STi (pair) StopTech 2 Piece AeroRotor 350Z Brembo Front 380x32mm Direct Fit Rotors No hat machining required , Zeckhausen Racing. StopTech 2 Piece Slotted AeroRotor Kits are designed to replace Original Equipment rotors on your 2003 2015 Subaru STi, while retaining the factory brake calipers. The same size as Original Equipment, the two piece, directional, floating AeroRotor offers improved cooling, braking and handling. AeroRotor rings feature StopTech's patented AeroVane internal vane design to optimize airflow. The rings are pre assembled to billet aluminum AeroHats for additional cooling functionality. Elongated drive pin slots allow separate expansion of the rotor and hat to resist coning. Developed using strong Inconel, the drive pin washers are the same that are used in aircraft engines and racing applications and are built to withstand extreme temperatures. These curved drive pin washers add tension to the hat assembly to reduce rattle. The drive pins used to affix the hat to the rotor have a a slightly out of round hole and are self locking. This allows the drive pins to move freely, yet securely, as the hat and rotor expand at different rates. Featuring a slotted design, the rotor's tapered slots allow for better dissipation of heat, friction material and debris and assure the pad material is in contact with the rotor every time the brakes are applied. Improved airflow is achieved through a directional design that minimizes turbulence and is an upgrade over Original Equipment rotors. All StopTech AeroRotors are manufactured in the United States.