MB Spares in Germany are offering a batch of E-Class Rear Axles (Some with Limited Slip Diff) For 95 - 99 Models and probably other years. Part Numbers are listed.
Priced at 818 Euro = 720 US Dollars (Plus Shipping)
Improve your gas mileage or Accelleration.
Site is at -
MB Rear Axle's
They also have loads more items for most models.
Look at -
Put in your Model (MB) and choose item from list.