The Audi 90 Quattro is a pleasure to drive. I drive a combination of interstate (about 26 miles) and city driving (about 4 miles) daily. The high quality interior is very comfortable. Fuel economy stays right around 23 mpg. Many people mistake the car to be much newer than it is. As far as problems, my fuel pump went out at around 95,000 miles. I fixed it myself for about $200 (pump and filter). Highs: Quattro models are unbeatable in the wet/snow. Quality, comfort, safety, handling. Lows: Parts availability, Audi dealerships don't really seem to care about their used car owners (except the parts department) My verdict: Quality ride that inspires confidence no matter the conditions.
My favorite features include the Quattro AWD, beautiful paint, a very comfortable interior, headlights made of glass that will NEVER haze up like plastic ones, and the rear fog light.
The trunk lid wire harness is problematic. Go to a quality car-audio shop to repair the harness.