The middle child of the A7 line, Audi's S7 flies under the radar. If you didn't notice the little fleck of red in its badge, you might mistake this four-door for its tamer sibling. It has the same creased hood, hexagonal grille, and fastback rump as the A7. But subtle differences—the quad exhaust tips, the rear diffuser, the larger intakes, and the contrasting mirror caps—give it away to those in the know. The S7 features standard all-wheel drive, an eight-speed automatic, and a twin-turbo V-6 good for 444 horsepower.