The original driveshafts of the S2000 is design at the stock ride height so when the car is lowered with coil springs or coil-over suspension then the driveshafts will be stretched about 10mm each side. This will occur a lot of stress to the driveshaft. As a result, the driveshaft will wear down in a very short period of time. J's Racing offer this spacer which the driveshaft can be 10mm closer to the outter side of the shaft so the shaft will not be stretched. This also allows the driveshafts to have longer life.