They are probably one of the most difficult of small cars to do major
engine/transmission mechanical services on although reasonable for
regular servicing. Transmission work usually requires taking the engine
out and because of the lay of the engine cyl heads/manifolds also
require a lot of dexterity. They also have complicated engine management
systems that require proper output analysis which usually need a trip to
the source for diagnosis. A good one is a treat though and a look
through specialist web sites such as baby-benz.com and svc.com would
give you an idea on what is in store.
Cheers