call a local dealership and give them the vin # and ask them to run a vehicle master inquiry, it will tell you all the dealership work it had documented.
If you were local, i would inspect it for you at your location.

Check underneath really good for transmission leaks, check the one touch window operation.

look at the engine compartment for oil , coolant leaks.

Check the seat functions and make sure all positions are working right.

How is the idle, oil color-condition, has it been maintained regularly.

Does it make noise flexing up hills,around bends?

You should have a reputable shop go over any car like that before purchasing it, make sure they are familiar with mercedes.