TODA RACING Honda S2000 F20C/F22C/K20A Up Rate Valve SpringsSpecial Order NO returns if ordered The need for increased performance has lead TODA RACING to design a single progressive coil spring to replace the STD double valve springs. As well as allowing valve lifts of up to 13. 0mm, the material and the coil springs natural frequency have all been optimized. Can be used up to 13. 5mm of lift *We recommend the use of Toda Up Rated Valve Springs to prevent coil binding and or broken springs.