Vogtland is confident its springs should be corrosion-resistant and sag-free for years to come. As with any German suspension company you can also rely on extremely stringent quality control, the best materials and the latest manufacturing techniques to ensure quality.Every spring set is carefully tuned for a specific application. A mixture of linear and progressive rate springs is used according to the specific requirements of the chassis. Spring rates are carefully calibrated for the engine and spec of the car they have been listed for. Unless otherwise stated in the fitting notes, all spring kits have been designed to work with standard shocks and TUV certification has been approved. Lowering amounts may vary for a special edition or sports models where lowering has already been applied at the factory.