Audi's A6 has comfortable ride and nimble handling, strong performance, great seats, and excellent fit and finish. The 2.0-liter, turbo four-cylinder works well, but has a raspy, less-than-luxurious engine sound. The 3.0-liter, supercharged V6 is smooth and punchy, while the 4.0-liter V8 in the S6 delivers effortless thrust. Front-drive versions get the four-cylinder and a seven-speed automated manual. All-wheel-drive versions can also be equipped with the four-cylinder, but use the smooth eight-speed automatic. The controls take some getting used to, but prove logical. A USB port is now standard for connecting mobile devices.