What others have said....

Get it checked out! Well worth the money, if it even costs you anything (Salim's in Colo Springs will do it for free--glad I did it, found out mine has a head gasket leak... I still bought it [an 88 300E] but it helped in my pricing).

Good luck to you, sounds like a nice car, but you should take it out and run it about 70-90 on the interstate. Mine freaking GLIDES out on the freeway, feels awesome! You'll want to see how it handles/rides at highway speeds, and also get on the brakes and see if the rotors are okay (if you get 'shimmy' when braking, I think that's an indication of worn rotors).

Are there service records with the Benz? Aware of any repairs in the last few years?

Take care, -Eric