For BMW 3 Series F31 Estate Genuine KYB Rear Suspension Coil Springs (Pair). We apologise in advance for any inconvenience caused. Coil Springs play an essential role in the vehicles suspension system. They are designed to compress and absorb shocks allowing us to experience a much smoother and more comfortable drive. Whether your current spring is broken, badly corroded or you just wish for a replacement part these springs are suitable.