Tein SKY94-AUB00 S.Tech Lowering Spring for Lexus IS300 Front spring rate: 4.9 kilogram per millimeter (274 pounds per inch) Rear spring rate: 3.8 kilogram per millimeter (241 pounds per inch) Front ride height: -33 millimeter (-1.3 inch) Rear ride height: -40 millimeter (-1.6 inch) Progressive spring rate design