The only thing I can really think to comment on is the vaccum pump. When something like that is known to produce catastrophic engine failure it seems to be unwise to leave it on a car. Even salvaging the newer style off a junk car is probably better than keeping the original design unless say there are no known cases of failure at under 150k for example on the original style pump. Tragically it might remain in service till it fails. Far too late to change it then. Other failures of course could cause engine problems but at least you have a chance to catch most of them while they are occuring. Merceded dealer might give indication of expected lifespan of original part over phone. That assembley perhaps should have been a recall as the problem was serious enough for mercedes to change the design. If you plan to own the car for years why not change it out now. Will never be cheaper to do. Peace of mind kind of thing as well. Have a pleasant trip.