I have a 2000 A6 with the 4.2 in it and I'm looking to replace my headlights with some angel eyes halo projectors. The problem I've been running in to is that they only list them for the V6 models. I've been told they won't work because the 4.2 has an extended front end, but I've been looking at them and they look like the exact same lamps. I just don't want to spend the $400 and then have them not fit.

 

I have the same year and engine as you do. Let me know how that goes and what you found to work.... I might just do the swap as well.