I have not had any problems that are out of the ordinary. ALL cars will have problems.
The only things I have done to this car are normal replacement items. Things like brake pads, replacing some vacuum lines, the timing belt, changing oil, and other little things so minor I cannot remember.
Yes I had the coil packs replaced under warranty. But this is not really an Audi issue per say. Audi did however step up and warranty them for all their cars with the issue. That is service.
I had some small issues when the car was under warranty; all taken care of without question by the dealer. Which I must say I bought my car on the other side of the US. I moved to Colorado and I have nothing but praise for the local dealer. They always took care of me like I had bought from them. They could have not been so friendly, many dealers are not.
Only real things that I hate is that my Bose speakers are crackling. But I can't be mad at that. The car has 115K and I blast the radio. It's just bound to blow. The only real drawback can be the price of some parts can expensive. But I expect this car to last well into the 200K range. So I expect to pay a little more for quality parts too.
I love my 1.8t Avant. I thought I would hate the fake leather seats. But now that I have a dog, these seats are a godsend. They never show wear, my dog can get all the dirt she wants on them.
The cargo room in this car is just great. I use it like a truck. I drive it like it's a Porsche. It really does handle like it is on rails. It gets great fuel mileage too.
I lust after an S4 Avant of the same era, but I don't want to deal with the maintenance on that car. The 1.8t is a much easier engine to work on. It's not hard to work on or to get to anything on the car. The front pops off like a Lego car in less than 15 minutes. That is a great feature that I wish more cars would do.
I do with the seats had more side bolster. I wish Audi had made a package that let me opt for Sport seats. I do have EVERY package that was available except automatic. Which I have to say the gear box is great. I am still on my original clutch too. I am sure it will go out soon. It has lasted me for 115K miles so far. More than normal. I plan on putting an uprated clutch in the car when I do replace it. The stock one is a little weak.
At 115K the interior is still in great shape. I have no squeaks or rattles... try that with a VW, Honda or Subi.
I have driven this car in INSANE snowstorms and it always makes it. Quattro is the best safety feature ever. I made it to work after the apocalyptic snowstorm where 7 feet had dumped in less that 2 days. My Audi plowed the road in front of the plows. I made it to work when NO ONE else had, which is good because I worked in a hospital at the time. You want to feel safe no matter what mother nature throws at you. Buy a quattro and good snow tires.