This spring has been designed to Drop In onto OEM seats. Suitable for the build-up to 700HP and 8000 RPM the springs seat pressure is 89lb at 35.60mm, 180lb @ 12mm lift, and comes with titanium retainers. We think this is now the best value spring on the market for Subaru’s EJ platform and should be your go-to spring kit for building up to 700HP.