algear, I agree with dboat - check to see if Mobil One makes a filter for your Audi. From my experience Mobil One filters are one of the best. Oil analysis on my Camry showed them to be better when coupled with an OEM air filter than both Amsoil (Hastings) or the K&N. Testing will vary from vehicle to vehicle of course.
Here is an interesting site you may wish to check out if you haven't already looked at it.
http://minimopar.net/oilfilterstudy.html
Good Luck finding the right filter.