Changing Spring Rate on C36 Update 2

Following is quoted from a forum discussion on benzworld.org:

Springs differ in two main areas... spring rate and spring length. Changing the length does affect the rate, but let's talk about springs in their static state.

Mercedes makes a whole series of different springs. They have different rates and lengths. These different springs are spec'd for different cars. Higher spring rates are generally for use in a heavier car. Spring rates can also be increased to vary the "sporty" driving nature of the car. Different spring lengths are used to vary the ride height of a specific car. The different thickness spring shims (often referred to as "pads" on the forums) are used to vary the space between spring perches, effectively changing the length of the spring.

For a given car, using the weight based on the number of options installed, the desired ride height based on the car market, and the intended ride quality, the intended spring and shim can be calculated.

Because Mercedes wanted a more "sporty" driving quality with the AMG models, a higher spring rate was in order. Depending on whether the AMG car is intended for US or Euro markets, a different spring length is chosen to provide different ride heights. Since Mercedes has a huge catalog of different springs from which to choose, the logical course would be for AMG to specify what the desired characteristics are, then choose the off-the-shelf spring that matches these characteristics. The W210 E-class springs are higher spring rates to handle the slightly increased weight of the car, so these were used. That's why the AMG cars come from the factory with springs that look like regular Mercedes springs and have regular Mercedes part numbers.