It might be hard to find in a search, but gsxr is the shopforum guru on rear end gears, and he has posted quite a bit on gearing for 124 and 123 cars.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".