HKS’ progressive rate lowering springs improve your vehicle’s looks and handling characteristics while maintaining ride comfort. Installing SF5 and Super Form springs will result in flatter cornering, more transitional response, and less weight transfer during rapid acceleration or braking. HKS springs are designed and manufactured using CAD technology and CNC machinery. Being constructed of an oil tempered silicon-chromiun steel wire that is thinner and stronger than ordinary steel wire, allows the springs to be formed at specific springs rates with fewer coils, thus offering more stroke and lower vehicle height. Each spring is shot peened, pre-fatigued, and electro-statically powder coated to provide a lifetime of uncompromising performance. Going the extra step, each spring is load tested for consistency and balance and then packaged with a spec sheet for the end users reference.