A mechanic friend of mine recommends replacing the MB rubber mounts with rubber oil tank mounts for a Harley Davidson....sounds goofy, but he says they last MUCH longer. He says you have to enlarge the holes slightly in the air filter housing, and also drill larger holes in the bracket, which obviously eliminates the threads, requiring the use of a nut and lock washer on the underside of the bracket to secure the mounts.
I haven't tried this myself yet, but he swears by it. I'll get around to trying it sooner or later....after I fix the other 35 annoying little things that are on my Mercedes to-do list.
Mike