You might find rear shocks for $75-100ea, but if you can buy Bilsteins (front) for newer strut cars for that much---let me know.
Either Sachs/Boge or Bilstein can be OE and both are quality parts. All MB cars w/leveling use Sachs strut legs. Most of the TRUE sportline Struts were Sachs!!
A W210 chassis with 42,000mi should not need this type of repair for another 50k mi.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
190E 2.3 ITS RACECAR
1986 190E 16V