About the only thing that has not gone wrong with the car is the engine internally. At any point in time, there is something leaking. Engine oil, or the very expensive Pentosin fluid that is used for power brakes and steering.
Power steering rack at 120,000 miles - $900
Numerous problems with heating and A/C have cost $1000 in the five years I've had the car, and at present the A/C does not work. Too scared to find out what the next repair bill is.
Every power window mechanism has had to be replaced, I did these myself for about $150 in parts each, and an afternoon. I don't have a lot of afternoons.
Most things in the cooling system have been replaced - radiator is expensive and hard to work on. And it's not repairable, it has plastic end caps and it doesn't just leak, it shatters. Between the radiator, auxiliary cooling pump and heater core, it was over $1000, and I did some of the work myself.
Fuel injectors needed replacing at 100,000 miles - cleaning was inadequate. Cost $250 and I spent an afternoon doing it.
It is worth noting that every time something has gone wrong with the car, the mechanic or the members of the Audi club all say "oh, yeah, they all do that".
By contrast, my Supra, with modifications to take it to nearly 400 horsepower, went 275,000 miles, with me spending less than $1,000 for all unscheduled maintenance over the life of the car.