I bought this car used and I was aware of a possible leak in the rear main seal. I had a mechanic do a full inspection on the car but he could not confirm the leak without steamcleaning the bottom of the car. I recently had a rear brake pad replacement at a Mercedes dealership and they too recommended repairing the rear main seal. So did you have yours repaired ?
Seals and gaskets seem to be a very common problem with these cars. I used to drive a 1991 Civic and it now has over 165,000 miles and the only major problem I had was replacing the radiator (wear and tear). I also own an Acura Integra with 30,000 miles and it seems like it can go another 100,000 miles without any problems. My Mercedes service records showed visits to the mechanic with only 17,000 miles ! But despite that I still love this car.