You need to post your question to the audifans mailing list. This will be by far the best and most helpful. Many mechanics and highly motivated and competent DIY'ers follow these lists.
you can sign up for the list at
Audifans. there are a couple of lists, the "quattro list" and the "s-car" list. I'd post your questions to both.
I've owned 5 different Audis and have had an amazing experience (much like this forum) with the folks on the mailing lists over at audifans.
Good luck.
---
Tom '75 targa