This system is built to last. Unlike bargain systems, we only use premium materials. The struts are made from stainless steel, with anodized aluminum spring seats, allowing years of height adjustment without worry of rust destroying the threads. The springs are made from a high tensile strength chrome silicon which greatly resists sagging. Spring seats feature a locking collar, instead of a set screw, which prevents a common failure. Thick stainless steel stabilizer bar end link mounting tabs are strong and allow adjustment for proper orientation. There's no worry of end link binding issues, and they will not bend like thin aluminum systems found on even some of the higher end systems. Lastly, each shock and damper is dyno tested for quality assurance. This system delivers the premium quality components and the driving experience you have come to expect from APR.