I gotcha beat,......I went for a 300+ mile cruise last saturday night.
I can now reproduce the sound some of the time while turning either way, and I have now strted to hear the same sound when braking and accelerating in a straight line.
Occasionally I can "feel" the "clunk" throught he steering wheel too. I don't think it's internal steering rack related though, it still feels more subframe/chassis related than mechanical operation related.
Steering input/feedback is not affected while clunking.
While the car was on the lift last tuesday I could not detect any loose suspension components, rack components, trans/eg. mounts, subframe connections, or anything else that indicates a problem.
I'm stumped. I work at an Audi dealership and so far we have not had any complaints with the A3 relating to this problem either.
Modified by feuerdog at 3:34 PM 7-31-2006