Integrated Engineering Valve Spring & Retainer KitThis high quality IE valve spring and titanium retainer kit features spring rates optimized to match your vehicle specifications and provide proper valve control preventing valve float in high power and high revving applications. Increasing your engines power output often comes with modifications that require more RPMs to get the most out of it, such as larger turbochargers, tuned intake manifolds , nd high output software tunes. Upgrading those