The 02+ A4 bulbs should be covered under warranty if you are still in your base warranty. so you shouldnt be buying anything. If you are out, and have to pay, you have to remove the headlight assembly, which requires removing the two Torx bolts on the top of the headlight and loosening the two torx bolts on each side of the headlight assembly, you will have to look, as they are down there pretty good. The headlight will then slide out and give access to the bulb. And yes, the bulb holders do burn and corrode out due to the headlight bulb terminals not being tight enough in the holder and will Arc and burn up. And yes you are suppose to align headlight afterwards, but if you mark where the assembly tabs are,and put them back as close as possible, you should be fine.