Well, I finally finished the job replacing the timing belt.
I am posting the experince to alert Audi owners to pay attention
to this crucial maintenance items.
I waited 17 years, and did nothing, knowing full well what can happen.
Anyway, the job was somewhat challenging the first time around.
One thing does bother me looking back:
there is a 6mm bolt, about 1 inch long, left over.
I know there a some 6mm bolts going into the block, but
I believe I put them all back in.
So I am keeping an eye on potential oil leaks, etc.
Moral of the story: make sure what you remove, put it back in.
(And don't keep any unrelated parts around which could subject you to
stress later on....
BTW, the car runs great, just like new!