I'll be frank on a couple things:
- I drive an ass-crap number of miles (~40k/year)
- My B6 has some sort of maintenance issue about once a month
- It's a 1.8t, with a Unitronic Stage 1+ tune, but it's still crappy on gas mileage
- I bought it with 98,000 miles, so my maintenance costs have been slightly higher than most.
That being said, I love the car, no scratch that, I adore this car. I love the ride, I love the way it drives, I love quattro in the winter, and I love the looks.
So, a few things I dislike about the car:
- It's a boat ... it feels every bit of its ~3600 some pounds
- The 5-speed has pretty short gears ... I'm around 3800rpm at 75mph
- My car has the infamous seat heater fire problem (Audi of America graciously replaced everything for FREE at 108,000 miles and I was the 3rd owner)
- The OEM HIDs are pricey to replace ... both my ballasts are starting to go and even if you get Chrysler ballasts and bulbs (same product), they are around $200/headlight
- The Climatronic tends to have issues ... Mine acts up only when both passenger and driver are set to high. It reverses and sends full heat A/C to both vents in an alternating pattern
- The non-Bose system is good for Audio (what I have), but the Bose system is typical Bose (no highs, no lows, it must be Bose)
- Gas mileage ... I had envisioned getting better from this car, but the combination of an underpowered motor for the car and quattro makes your averages suck
Now, for what I love about this car:
- quattro ... I can't say enough about it. If you've never owned an AWD car, this system is just superb. In conjuction with the ESP, this car is nearly impossible to put sideways unintentionally ... like, if the system even starts to see your ass-end swing out, it automatically straightens itself out
- Boost ... well, the stock k03s might be an underpowered turd of a turbo, but throw a Stage 1+ tune at it to 18psi and the car wakes up ... sounds like a bat out of hell at full boost (even if you aren't going very quickly)
- RNS-E ... well, if you splurge like I did and installed an OEM Audi RNS-E, you get the benefits of the integrated cluster with Navigation. The early 2002s with Navi came with the color FIS, but all the rest of them came with the red FIS which requires a quick off/on cycle of the RNS to get it to appear. This is extremely awesome for directions to have it in the cluster.
- 2002 Cold Weather Package - the 2002s, as an introductory year, came with rear heated seats. These are more of a novelty than anything else, but it was cool showing that off to the girlfriend's parents when I drove them around for the first time.
- 2002 Sport Package - again, the MY2002s came with the lowest OEM suspension of any Audi ... look at the pictures of my car ... it sits at about 1-1.5 finger gap around on the stock springs and shocks

So, as for the costs of ownership, well, as I said, I drive a crap ton of miles. Here's a quick breakdown of my costs since buying this car last May:
It's pricey, but remember, most of those costs are fuel and mods. The actual repairs aren't too terribly expensive. My car is repaired at an independent shop @ $60/hour, so compare your own local labor to that if you need a more apples-to-apples comparison.
Here is my gas mileage over the last 10 months, approximately 32,000 miles of driving (93oct solely):
In the end, I love this car, even if it does cost me a bit of money. Well worth it for the benefits in my opinion.