after 2 years of meth abuse, we cracked one of the intake valves and did some damage to the head. fixed the head, then turned the meth off when we realized just how much timing was being pulled (APR 100 octane software has very aggressive timing, and the time required for the meth to take effect is long enough that the ECU needs to step in to pull timing so things don't get broken). i'm getting a bit off course here. even on the 91 or 93 programs, the car has plenty of go.
other than us doing the head, it's been the absolute model of reliability. ours is a 5spd avant manual (02-03 were 5spd, 04-05 were 6spd). i can't talk about the auto, other than to say that i'm sure it's bulletproof, and boring. i like the sedan, but the avant is so much more useful IMHO. especially if you've got, or are planning a family.
you can use a rear facing child seat, but it'll be a bit cramped. my wife liked the car so much when she found it, that she didn't care that for the first year, she had to sit a little close to the wheel.
problem areas we've had that i can recall:
-1.8T coils (always have a set in the trunk)
-1.8T valve cover (replaced it at both timing belt changes)
-control arms (we've only ever done 3 arms of the 8, and that was a one-time thing)
-the brakes have a bit of a vagueness to them on initial application, but they are otherwise amazing. we updgraded the fronts to B5 S4, but they're still not enough. ideally, we'll go to something bigger and better for when we go back to the track
-we replaced the rad once because it had small leak
-the fuel level read incorrectly for 2 years. i went to replace them, realized i had the wrong parts, plugged everything back in, and it all works fine now
-the original steering rack clunked under certain circumstances (tight reversing turns out of the driveway, for example), so we replaced it with a rebuilt rack that is even noisier. that rack has been in there for about 3 years now.
-i hate the dash-mounted cupholder, and the cupholders in the armrest. i believe that later versions had cupholders in the centre console
-the hard plastic rear of the driver seat has popped out. 2 years and counting now. i've had the parts to fix it for 6 months. no biggie
-find a car with the Bose system, it's **MUCH** better than the non-Bose
-xenon headlights are better (but hugely more expensive to replace) than the halogens
we've put 160K on it since buying it off a wholesaler that got it from audi corporate. it's been a joy driving it, and we can't possibly ever think about selling it. we've tracked it, driven it to waterfest in dirty jersey, ohio, and all over ontario. it's done literally hours of donuts in the snow, and last year in one of the city-shut-down snowstorms, i apexed the 403 at the bottom of the mountain in hamilton at breathtaking speeds with nothing but confidence.
if you haven't experienced quattro with good winter tires in a snowstorm yet, your mind will not believe what is happening.
the manual with the traction control off in the winter will make you sell your skis or snowboard because the thrill of drifting all the way to the hill will make.
the 3.0L is not particularly good on gas (our A4 gets about 600km/tank), and it has a tendency to require expensive repairs, as i recall. pricing is whatever the market will bear, so keep checking the autotrader as you have, and best of luck to you!