Tein SKJ14-AUB00 S.Tech Lowering Spring for BMW 3 Series Front spring rate: 3.4 kilogram per millimeter (191 pounds per inch) Rear spring rate: 10.6 kilogram per millimeter (532 pounds per inch) Front ride height: -22 millimeter (-0.9 inch) Rear ride height: -27 millimeter (-1.1 inch) Progressive spring rate design