The thin metal on the top of the shock towers is a known weak spot on the E30, E36 & E46. The metal tends to crack over time, especially when rigid dampers are used. This reinforcement, made of 3mm thick steel, is designed to be mounted on top of the shock absorber tower (in the trunk). This spreads the pressure over a larger surface area to prevent cracking. It can also be used to repair an already damaged shock absorber tower by welding it in. Weighs 50 grams each.
The price is per pair.