I purchased in MI with 110k miles after my 14 yr old Mitsubishi Eclipse wasn't worth fixing anymore. With regards to comfort and luxury, this was certainly a step up, growing up with only Japanese cars. Build quality, heaviness of German engineering is evident, but not without flaws. I had to put some money into the car considering its age. Maintenance/Repair: Timing belt-$800, rear coolant flange-$200, rear window regulator-$360, battery-$190. Otherwise, it's a great car. Very comfortable, nice features, and a great drive. After an APR tune on the ECU, it has 235hp vs 170hp previously, which makes it fun and adequately powerful. It hasn't had a huge effect on mileage, except for a heavy foot
I have owned this vehicle since new. At 145K miles, engine gave out, with $6K repair needed to replace major engine components. Serviced regularly with oil change q 5K miles. Never driven hard, still has original clutch. However, both catalytic converters had to be replaced at 82K and 110k miles. Multiple parts inside needed replacing as well. When Audi USA was contacted over the engine problem, they blew me off (which I would understand if this engine defect were unique to my car, but it isn't!) I would highly recommend that anyone buying A4s with 1.8 or 3 L engines carefully read other similar events on the internet before buying a used Audi. Don't make a big mistake.
Bought my 2003 A4 with 95k miles on it. It had already had the timing belt replaced. The dipstick tube cracked and broke off when I attempted to check the oil. The coolant flange on the back of the engine poured coolant constantly, and the turbo leaked oil. Even after replacing the coil packs, fuel filter, and spark plugs the engine still had a rough idle. Ended up replacing every plastic check valve under the hood to no avail. Found that the crankcase vent tube cracked and broke off causing a vacuum leak. Went to get in the car one morning after rain, and the floor was 2 inches deep in water. Took forever to fix that issue. Too many issues to list. These things are LEMONS.
I bought the car new over 7 years ago now. Should've known after 2 weeks when my AC compressor blew up that this was going to be a love/hate relationship. I've had it in the shop for: AC compressor, AC condenser, engine speed sensor, engine temp sensor, power steering pump, power steering rack, brake light switch, instrument panel malfunction, rear window regulator, and of course the common coil packs. And just now, the AC compressor blew AGAIN. And this is only off the top of my head. It's a shame because i LOVE driving the car, it handles like a dream, is great in the snow, but it's just NOT reliable.
Some things to look out for if you're looking for a used 2003 audi A4: Audis are known for guzzling oil and this car is no exception. If you are buying a used car you may need to flush out the heater core. It has a flaw where it will accumulate gunk over the years and the heat will not work until it is flushed. Also ask about how recently the timing belt has been replaced. If yours snaps, the "interference engine is toast.