I would never use it. A quality, clean engine oil is all that you need. Use Mobil 1, what better protection could you get for your car? Mercedes even voids warranties if they find any additives were added to the oil. Your is probably not under warranty, but goes to show a point about how strongly MB feels about this.
Mobil 1, Amsoil (at $8 a quart!) and other quality oils are formulated with all the additives and lubrication properties that are needed. Engineers spent a good deal of time formulating oil. Do you think they would have overlooked anything that would not make their oil a superior product. Don't mess with a good thing.