H&R lowering springs for the 135i are a great choice for the conservative driver looking for a little more performance without sacrificing ride quality, this kit lowers the front of the car 1.8 inches and 1.3 inches in the rear. Give your 135i the aggressive competitive stance with H&R. Every spring produced by H&R comes from the H&R ISO 9001 certified engineering and manufacturing facility in Germany. All H&R springs are produced from a special 54SiCr6 spring steel, which has strength rated at 290,000 psi resulting in unrivaled tensile strength and resiliency. "Each spring is then sent through the H&R exclusive “SuperBlok™” system, which cycles each spring to ensure that sagging will never occur." Combining high-quality materials with advanced designed tools and techniques makes the final H&R product lighter and more durable than other automotive coil springs. At H&R product design and development is of the highest importance. All H&R springs are “cold” wound on specially designed CNC machinery and then time-tempered to re-align the molecular structure of the steel to ensure quality and durability. All springs are shot-peened to increase the service life of each spring by more than 200%. Each spring is then sent through the H&R exclusive “SuperBlok™” system, which cycles each spring to ensure that sagging will never occur. Lastly, the H&R special powder coating process coats each spring with a flexible and durable finish that is highly resistant to corrosion, chips, and scratches. At H&R we care about quality –– the whole production process, from start to finish, is done in-house to ensure the most consistent, highest quality product possible.