Just make sure you get absolutely everything you can fixed while it's still under warranty. If it's out of warranty and stuff starts going wrong, get rid of it ASAP. My wife had an '02 Allroad that we stupidly kept putting money into at around 120k miles, then finally gave up and traded it on an A3. The Allroad had previously needed major work to the air suspension at around 60k to the tune of about $10k. The A3 has been mostly trouble free, but has had some electrical issues. Both front doors have had to be rewired because the windows would randomly fail to go up and down. The ignition control module had to be replaced because it wasn't supplying current to the radio to let it know the key was on, so the radio would shut down after 60 minutes of use.
Air suspension on most passenger cars is going to be a recipe for heartache, but the Allroad definitely has a less than stellar reputation for reliability. Electrical issues are slightly more common on Audi's than on other makes, so buying with a warranty is probably smart. On the other hand, the drivetrains are usually bulletproof and the interiors are usually of better than average quality. Ride and handling are also excellent. Just make sure to keep up with maintenance!
I own 1995 S6 with 172k miles on the clock. Original engine, original turbo. I had to have the head gasket done earlier this year but otherwise, it's been very good. Audi has very high build quality, with some questionable electrics.
I had an S8 for a while. Incredible car, but costly to maintain. I wouldn't worry too much about newer A4/S4s. One BIG thing to keep in mind; go for a standard transmission if you can. German automatic trannies made for Audi, BMW, and others by ZF Friedrichshafen don't go much more than 100K without needing a rebuild. Plan on $5K (or more) for that.
Also, head over to Quattroworld and search for things to watch out for. It's the "WFF" of the Audi owners world.
My grandma used to recite this little ditty to my sister:
There was a little girl
That had a little curl
Right in the middle of her forehead.
When she was good she was very good
But when she was bad she was horrid!
Most European luxury cars fit this description. Expensive up front and very expensive when they start to go south but delightful in the sweet spot. The trick is to know when to hold and know when to fold.
Love it, we bought with 100,000 + and it now has 160,000. Only thing we made sure the car had, in our shopping for that car, 1.8 liter or 2.0 liter (newer have 2.0) for fuel economy, and, that the timing belt and water pump was done. Previous owner had done, and had paperwork to prove it. We'll need to do that again, any second now ourselves (160,000k its scheduled). My understanding, as far as the engine goes, that is only thing that can be a problem on these cars. If you don't maintain or keep on scheduled maintenance, that's a concern. If you make sure that's already done (or in your case, looks like a newer version) that you do it when scheduled (I think 80K or so), should be money. Also, electrical can be an issue, we haven't had anything come up, crossing fingers.
I think some people do sell them just before that type of service is done, but I've found that most vehicles, used, have a certain niche problem and you'll see that sellers point out that that specific thing has been done. You'll see a lot of Audi's for sale on craigslist listing that the timing belt/ water pump done at xxx,xxx miles, and provide paperwork to prove that is the case. I am looking for a 4 runner right now, and my mechanic said 90-95 have head gasket issues sometimes, I see lots on CL with new headgaskets. Seems like a good thing to know when you're looking for a car, what are the typical problems, and are they ok for you to maintain, or are they too expensive or difficult to maintain, then you can avoid them. As for the A4 avant, my opinion, timing belt and electrical are the big potentials, and I think they are worth the risk, and risk can be reduced by maintenance, regularly, from an audi dealer/ audi specialist. We've also found the dealer to be great customer service, and no more expensive than our neighborhood garage. And they give us a loaner, or ride to work if we need. Same cost as other places, that don't give us cookies and snacks or a ride if we don't want to wait.
I have a 2004 VW Passat GLS wagon (A4 cousin) with 153 k miles on it, and it's been a steady performer since day one. It has the 1.8 liter turbo engine w/automatic transmission and front-wheel drive, and consistently gets over 30 mpg on the highway, about 22 mpg around town. With the back seat folded down, the deck is almost 6' long, and I have slept back there in emergencies....and it'll take a 10' flyrod from tailgate to windshield without breaking it down. I have had no engine or transmission issues, but electrical things pop up from time to time (like the driver's door latch that controls some of the interior lights and the headlights-on chime). I bought it at Auburn VW new, and they've done all the servicing on it, and they've been awesome. I've had 3 fishing buddies with me in it with all our gear in the back and on the top for weekend trips, and it's performed well, though it doesn't have much ground clearance with all that weight....I've thought about putting oversized wheels and tires on it to give it more clearance. Unfortunately, the Passat wagon isn't made anymore...the only wagon now is the Jetta Sportwagon, and the ground clearance is zero. And the Passat sedans are now made in Tennessee, I think, so who knows? I'm gonna hang onto this one till it dies.
good post as I just bought a '99 A4 1.8 turbo for the kid. it has 73K and I am/was/still am worried about maintenance down the road. We've only had it for a month and he likes the mileage it is getting (compared to the '96 Explorer he was driving). I am noting the PM schedules, timing belt and water pump