The Bilstein 04-07 BMW 525i B3 OE Replacement Coil Spring - Rear is a direct fit replacement part for the BMW 525i model from 2004-2007. This coil spring is designed to replace the original equipment spring, and is crafted from a high-quality material for a long-lasting performance. It is designed to offer an improved ride quality and handling performance, and is backed by a limited lifetime warranty.