Tein SKY94-BUB00 High.Tech Lowering Spring for Lexus IS300 Front spring rate: 4.6 kilogram per millimeter (257 pounds per inch) Rear spring rate: 3.6 kilogram per millimeter (224 pounds per inch) Front ride height: -17.5 millimeter (-0.7 inch) Rear ride height: -24.5 millimeter (-1 inch) Progressive spring rate design