Michel,
The clunk is back in full swing. I am still in debug mode. I met an awesome Porsche tech who I will ask to work on this with me. He has no preconceived ideas of what this might be, but when I described the problem, he said "sway bar links, thrust arm bearings, tie rod ends, engine mounts, and strut tower bearings." So, I think he gets the picture. I'll let you know what I find out.
CL