The Bilstein B12 (Pro-Kit) is the result of two companies atop their industries collaborating to present the ultimate solution in suspension for the passenger car market. The shock absorber experts at Bilstein and the spring professionals at Eibach used their 120 years of combined experience and knowledge to spawn Performance2. The B12 system consists of four high performance Bilstein dampers, four hi-tech industrial Eibach lowering springs and together you have the best handling, most comfortable direct fit suspension system available today.