I have not heard of a four lug pad in the rear (only front). Each lug on the spring pad represents 5 mm of pad - 10 mm of ride height. If you have blue springs, the Mercedes TDM specs 2 lug pads and every 124 car with blue springs that I've seen has 2 lugs. For red, it'd be 3 lug. You may want to try thinner spring pads.

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Brian Toscano