The radiator leaked and had to be fixed: about $100.
Two of the power windows don't work.
Shocks have gone bad. But hey, they're 17 years old!
I had to get a new muffler: $75.
I have been extremely pleased with this car. I was able to purchase it for @2000, and I can't think of anything I'd like more. Audi was ahead of their time in designing this car.
It's a good 'sports sedan'. The acceleration is decent, and the handling is good. On corners, body roll is a little more than I'd like. The exterior is very stylish for its time. The interior has enough room and is comfortable enough. The seats have good support.
We currently own a 1984 4000S Quattro and I understand the body roll thing, but if you put a stiffer suspension and shocks on it then it's a perfect ride that can give an S4 a run for it's money. Hey we only paid $500 for ours and it's in great shape it just needed some work here and there but hey what car doesn't?