I've replaced the shocks with less mushy ones for better stability. Front wheel bearings were worn, rotors and pads worn, muffler replaced. Other than those wear items, just maintenance.
After 13 years on the road this car is still fast and quiet with great comfort and handling for a car of its size. Stomp on the pedal and as the revs climb those 24 valves kick in like a turbo (without the turbo related problems). All the gadgets and mechanicals still work solidly. Corners solidly with only minimal understeer. Contrary to some other reviews here I don't think there are so many 160k mile cars out there that still run practically like new. No rust on mine. Unfortunately parts that do have to be replaced can be relatively expensive. It's a high quality car that balances performance with comfort and comes with all the goodies.
Just wanted to say that I am a fellow former Audi 4000 CS Q owner. I totalled that car and I'm now looking at a beautiful Acura Legend. It's encouraging to see your review.
Audi 4000s kick ass.
I have a 1987 Acura Legend. It does take off like a turbocharged car, feeling like it has a lot more than the 160-170hp as represented. My vehicle runs like new with 153000 miles and has had no major problems. The only upgrades I have done to the car are bosch platinum +4 plugs and good quality spark plug wires. I also replaced the oxygen sensors and the car has run perfectly ever since. It is still a great ride after all these years.