Update: Just turned over 90,000 miles and everything is great. I did have the dealership perform a four-wheel alignment, since one had never been done, and while it was there, they replaced the fuel pressure sender and intake flap runner motor under a service campaign at absolutely no charge to me. I had had no indication of any problems with these items, and they said mine still appeared fine, but the updated parts were a preventive measure. The alignment only required very minor adjustments, and everything else on the car checked out perfectly. So, a good bill of health to take me to 100,000 and beyond!
Update: 95,000 miles.
Since my last post I have had the front engine mount replaced, also known as the "snub mount" on Audi forums and "jounce bumper" according to Audi terminology. The old mount was nowhere near failing, but it did have cracks in it, was easy to get to while the front pan was off for oil service, and as usual a good preventive maintenance item to take care of. The part, directly from Audi, was about $20 and the labor was somewhere around $100.
I am continuing to service the car every 7,500 miles with Liqui-Moly full synthetic 5W-40 oil and Liqui-Moly's anti-friction MOS2 oil additive, and it runs beautifully without the excessive oil consumption reported by others.
The BEST thing that has been done since my last post was the addition of a new set of Continental ExtremeContact DWS tires to replace the Hankooks. What an unbelievable difference this has made. This car has never been so smooth and quiet, and the ride is markedly improved as well! The Hankook tires wore very evenly and still had plenty of tread left, but they were always noisy since new and will not be missed.
Otherwise, nothing new to report. The car still drives like new and makes every trip enjoyable.
Update: 105,000 miles.
Since the last post, but not long after it, I did need to replace the A/C compressor and drier because the system's cooling was diminishing at idle. After studying the forums a bit, it seems these cars have somewhat weak compressors and mine actually lasted longer than many usually do. So, this was my first real disappointment with the car, since I have never had to replace A/C components in my other cars, none of which were as new and expensive as this one.
All of that said though, everything else is great with the car. It's been so great, in fact, that I decided to shake up my life by buying something which could potentially ruin me: a 2000 Land Rover Discovery. I am keeping the Audi because it makes a lot of sense to own, but the Land Rover now exists in my life to relieve the still-beautiful and like-new Audi of duties such as trips to the home improvement store, my nomadic moving tendencies, and trips to Tybee Island where parking a pristine vehicle like it can be a risky proposition.