WRX STI Spec C Type RA-R At the end of October, 300 2007MY WRX STI Spec C Type RA-Rs were open for ordering. These cars are based on the WRX STI Spec C. The wheels are changed for 18-inch (460 mm), STI-branded, Enkei-made, white wheels. The engine has been blueprinted and balanced. It produces 320 PS (235 kW; 316 hp) of power. The suspension is built with the latest STI parts from the STI catalog. The front brakes are 6-piston Brembo brakes. The turbocharger is based on the larger S203/S204 twin-scroll unit. The brakes are made so that they change from silver to gold when heated from usage. The rotors are slotted. The 2nd R in "RA-R" is stated by an STI engineer to mean "radical".