Convert Your Expensive Factory Suspension To Our Exclusive Coil Spring Suspension. End Your Active Hydraulic Suspension Problems Forever... Strutmasters 2002-2012 Mercedes Benz SL55 Four Wheel Hydraulic Suspension To Passive Coil Spring Conversion System is the perfect solution to your computerized suspension problems. Designed to be very affordable, you can convert your ENTIRE active hydraulic suspension to use passive struts and coil springs for less than the price of replacing ONE Original Equipment strut at the dealer.