Prizefight: Porsche 911 vs. Audi R8

In his latest prizefight, Brian Cooley looks at two high-stepping German cars, the Porsche 911 Carrera 4S and the Audi R8. Both cars have all-wheel-drive and both top $100,000 in price, but which is better? Brian compares powertrains, handling, design, cabin electronics, and a special category for cars in this segment.