The Audi S7 is a hatchback that calls into question every prejudice you've ever had against that practical body style. Beautiful, and beautifully detailed, the five-door mid-sizer is a suave derivative of the Audi A6 sedan, but it's much more than that--it's serious competition for BMW's 6-Series Gran Coupe and Mercedes' CLS. A part of the A7 / A6...