A tail-light bulb has gone out on my 2001 A6. Surely it is not necessary to only let the dealer replace it as the manual advises..hmm?

 

No...not a real problem. You just have to make sure you get the right one. Take the bad one in with you to match up the contact points and the 'pin' positions on the side.
Peppy Boys got it right for me on the second try. Also - no need to take the lamp assembly out - just pull the lamp holder out from the back side after you get the access panel out of the way.

 

I managed to replace my tail light. The biggest problem was getting access to it. After much struggling with the trim I discovered there was an easier way - simply remove the jack and tools from behind the panel. Unplug the power from the lights assembly, then remove the assembly by squeezing the two large tabs. At Pep Boys their handy dandy electronic bulb finder led me straight to #2357A.
Why couldn't they have told us this in the manual? Would have saved this owner about an hour of cursing and much searching on the web - next time it will take 5 minutes.