What is the purpose of the self leveling suspension? What does it really do and why does Mercedes use it in some models but not others?

Besides E class wagons (123, 124, 210, and 211), Mercedes has used it in some versions of the W201, W124, W126, W140, R107, and R129. I get the concept of compensating for a heavy load in a wagon or even a big sedan, but what was the idea of using it in the W201, W124, R107, and R129? Besides compensating for a heavy load, what else does it do? If it has such great benefits in some models, why not use it in all models?

Just curious. Thanks.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230