1996 Audi A4 B5.

it is fairly easy to do with the correct kit, but you will need to change the headlamp units for ones with Projector's in them, they are fitted to the later B5 (99-2001), if you dont change the lamps will be illegal and you will fail the MOT !! i looked into doin this on mine B5, the lamps 2nd hand are bout £70 on ebay, then the HID kit price on top.

Thanks for that. Sounds like it could get quite costly.Might have to think about it.

Good info there.... Also make sure you do all of the wiring properly and that the kit is of decent quality. HID's require a ballast and none of the Halogen wiring is reuseable because HID's pull a very large amount of current when they first switch on and wiring that is too thin or not installed with the proper bits will melt and cause an electrical fire.