I have a pair of customized A6 OEM Hella bi-xenon headlights , I'm not 100% sure which A6 models they compatible with but I believe the part numbers are :

Right 4B0 941 004 BF
Left 4B0 941 003 BF

The headlights are used but in overall good shape and have a flat black paint job and Morimoto CCFL halos installed.
The headlights were resealed with OE Butyl rubber. All custom work done professionally and never used since.

Includes :
OEM Hella ballasts
Brand new Morimoto 6000k D2S bulbs
Clear Signal bulbs
Brand new Morimoto CCFL inverters and rings ( installed ).
You will need to hook-up the two wires that power up the halos to your desired power source ( parking lights or DRL ).

Please feel free to PM if you have any questions.

Asking 650$ shipped pretty much anywhere in USA / Canada.