The Bilstein B3 01-06 BMW 325Ci Series Replacement Rear Coil Spring; Sport Suspension Only is an aftermarket suspension part designed to replace the stock rear coil spring in 2001 to 2006 BMW 325Ci series vehicles. This part is designed to provide a sportier ride and improved handling performance. The spring features a progressive rate design that offers a comfortable ride while still providing improved handling. It is made from high quality steel for increased durability and longevity. This part is a great way to upgrade your BMW 325Ci's suspension and improve its performance.