I have xenons on my 2000 A6Q
Yesterday morning I noticed the light 'colour' was looking kinda strange when reflecting off cars in front, so I pulled up to take a look from the front.
One lamp was normal, but the nearside was very yellow.
Later in the day I swapped the bulbs over to check if it was the bulb or the ballast etc, and the problem moved so I guessed it was the bulb.
Deep breath and into my local Audi dealer (Reading Audi) fearing the worst>>>>
£106 for a BULB!!!!!!!!!!!!!!!!!!!!!!!!! (that's close to $150)Shopped around on net for a bit (Phillips D2S HID bulb) cheapest I could find was £97 and 5 days for delivery. Back to Audi who sourced the part and delivered it by courier next working day.
Ouch....