BMW F32 4 Series Yrs 2013 - on Diesel & Petrol Models excl M4 Jom Blueline Coilovers Kit Description Use your existing top mounts Quality assured via German TüV standard compliance Springs are manufactured from highest grade SICR steel. Springs are forged using the more reliable 'cold-drawn' method. Some competitors use the hot-forged method of manufacture, this has an adverse effect on the springs' tensile strength: i.e. consistent tension Following the forging process, a temperature controlled oil based treatment is applied to the spring to ensure that the required hardness and tension is reached, thus giving full operational effectiveness throughout the springs' entire lifecycle The steel is initially treated with Zinc-Phosphate, and finished in an Epoxy Resin to provide effective protection of the spring The shock absorbers contain both oil and gas. The gas serves to cool the oil to produce a more consistent operation The shock absorbers improve damper performance by 30% compare...