Most anything mechanical can be fixed with reasonable effort. Look undercar for any rust starting with the jack pockets. Remember that the rust will have spread under the paint/coatings to several times the area you can see. So don't accept much rust showing (and I DO body work & welding). Rust and Bosch kill Mercedes!

I just looked at the CL listing. It doesn't look too bad. The oil cooler line looks new which shows that someone has at least tried to love it and the ALDA is still there indicating that it hasn't been messed with too much. Both are good signs. The mileage is low enough that it's probably decent mechanically though you might want to get the trans looked at before you pull the trigger. Check to see if the odometer is working - a lot of them fail and it might have a TON more mileage than it shows. Just make sure the odo moves on the test drive.

Dan