2002 Audi S4 quattro AWD 4dr Sedan (2.7L 6cyl Turbo 6M)
I couldn't be happier with the stock performance of this car. The price to performance and features ratio of this car can't be beat, and simple upgrades can make this car truly track ready. In the Northeast or snowy climes, no car on the road can touch it (B6 S4 and RS 6 aside). But quality, reliability, and dealer service is absolutely brutal. Electrical system problems are Audi's specialty, but I have also had problems with everything from rattles to rivets popping to coolant pumps failing to leather spalling to ... Service quality and knowledge from dealers is poor (e.g. Audi service does not feel it's necessary to rotate tires).
Low end torque, brakes
Improve quality. Get rid of the 50K free service and put the money into making the car reliable.