Upgrade to Greddy stiffer spring rate valve springs to prevent valve floating under high RPM. This is a good upgrade for anyone with stock or aftermarket camshafts. I got them and i never installed them because i sold my motor. Regular price $200 my asking price is $150 obo

Part Number: 13523600

Model: Silvia - S13/ S14/ S15

Desc: GREX Valve Spring

Notes: PS13 / S14 / S15 / RPS13