The H&R 01-06 BMW M3/M3 Cabrio E46 Sport Spring is a suspension upgrade designed to improve the performance and handling of the BMW E46 M3 and M3 Cabrio. The spring is designed to lower the car's center of gravity, reducing body roll and improving cornering. It also provides enhanced stability and a more aggressive stance. The spring is constructed from high-tensile chrome-silicon steel and is powder-coated for corrosion resistance. The kit includes two front and two rear springs, as well as four bump stops.