Just to comment on something Dsinger said about using a ACEA A3 rated oil. There are only a couple of synthetic oils available in the USA that meet the strict European standard. Mobil 1 15W-50 is the only Mobil 1 that meets this standard. Valvoline Synpower 5W-40 is another. Castrol Syntec 5W-50 also claims to meet this standard, though there has been some debate over whether or not Syntec is a real full synthetic, but that's another subject. No oil, be it "dino" or synthetic that is below xxW-40, meets the A3 standard. Porsches come factory filled with Mobil 1 0W-40. I don't know about the factory fills of the newer Benzes, but I am willing to bet it is at least a xxW-40 oil. Again, because anything thinner does not meet the A3 rating for high performance/extended drain interval oil.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section