After 3 months of living with a rattle that sounded like a Yugo on my A5 I have figured out what it is. Many posters have mentioned this or something similar that had been solved by having the speaker harness wrapped in foam by their dealers. My dealer spent two days trying to solve this for me and could come up with no solution, apparently the tech couldn't even locate its exact location. While driving on rough roads the drivers side kept rattling, after much frustration even trying to locate with a stethoscope I couldn't find the source. I have finally figured it out. Yesterday while driving on a rough road I kept pressing on different parts of the door and dash - when I pressed against the small rectangular panel on the dash that surrounds the circular light switch the rattle stopped. I have repeated this dozens of times and it always worked. Now when my A5 returns to the dealer for a new muffler I will have them address this.