Teahead, did you ever find the source of your 'clunk?' I chased a very similar sound for over two years, replacing exhaust hangars, differential mount, inspecting everything I could think of, to no avail. Pulled off the right rear wheel to inspect the brake caliper, thinking it may have been loose. While doing so, and tapping around with a rubber mallet on the axle, I heard "the sound." The retention springs holding my handbrake shoes tight were shot, and had no tension in them. Bingo! The brake shoes, while still in the correct position, were loose enough that whenever going over even small bumps, reflectors in the road, etc., they would be jarred enough to bang around. I went ahead and replaced the shoes, retaining springs, etc. with the Mercedes parts (I am five minutes away from the Irvine classic center). Silence!
