Mercedes color codes certain parts to denote tolerances in manufacturing. Your springs should have a slash of either blue or red paint which will tell you which spring pads should be used for a given points value. Based on 50 points and the 126 321 17 04 spring, blue-marked springs would use the 18 mm thick pad and red-marked springs would use the 23 mm thick pad. Unfortunately, the 126 321 18 04 spring does not appear to be compatible with your car but if you happen to have the red-marked springs you may be able to make it work with the 8mm thick pads. Mark