The drivers side headlight light keep's going off and the side light won't come on at all. I'm new to Xenon's and don't have a clue. It is actually on my friends 54 TT 3.2 roadster. She rang Audi and was quoted about a £1000! Does she have to replace the whole headlamp unit or can the bulbs be replaced? And if yes are they easy to install? Any help is much appreciated.