Tein SKG72-AUB00 S.Tech Lowering Spring for BMW 3 Series Front spring rate: 3 kilogram per millimeter (168 pounds per inch) Rear spring rate: 8.5 kilogram per millimeter (593 pounds per inch) Front ride height: -39.5 millimeter (-1.6 inch) Rear ride height: -19 millimeter (-0.7 inch) Progressive spring rate design