This is the car that the recently reviewed Audi S7 is based upon, so it's no surprise that the two vehicles are remarkably similar in styling from B-pillars forward. Then again, the same could be said for practically all of Audi's sedans and coupes.
The S6 is a traditional sedan with a proper trunk and a more upright stature. Its looks are more conservative than the flowing lines of the S7. Even when decked out in $1,075 Estoril Blue crystal effect paint, the 420-horsepower S6 seemed to blend in wherever it went. Personally, I think that this sort of Q-car camouflage is a good thing. When you're behind the wheel of a car that breaks speed limits with the S6's ease, the last thing you need is a bunch of onlookers gawking.
The S6's fenders proudly display "V8 T" badges, while the spec sheet boasts a designation of 4.0 TFSI V8. In English, that means that the S6 is powered by a 4-liter, eight-cylinder engine that is force-fed air by a turbocharger and sips gasoline via a stratified fuel injection system. Power at the crank is estimated at a maximum of 420 horsepower and 406 pound-feet of torque.
This V-8 engine also features cylinder deactivation technology, allowing it to reduce the number of active cylinders for increased fuel economy when maximum power is not needed. The EPA estimates the S6 will get 20 combined mpg, which breaks out to 17 mpg in the city and 27 mpg on the highway. We only managed 17.1 mpg over the course of 480 miles of testing -- over 250 of which were relaxed freeway cruising.
The seven-speed S-tronic dual-clutch automatic transmission features normal and sport programs and a manual shift mode. Normal and automatic modes feature throttle-blipped downshifts, which is normally a welcome addition, but I found that our S6 had an odd tendency to occasionally fire off a downshift even when I was just casually slowing for a traffic light. The sudden jump in revs combined with the light brake pedal pressure for what should be a smooth stop would cause the sedan to lurch forward awkwardly. After a few such moments, I lost my confidence in the automatic programs and did most of my driving in the manual shifting mode, controlling my shifts with the S6's steering-wheel-mounted paddle shifters. Interestingly, Senior Editor Wayne Cunningham didn't run into this issue with the mechanically identical Audi S7, so I'm not sure what the explanation for my experience could be.
Power leaves the gearbox and is split between the S6's wheels (on our S6, these were the optional 20-inch wheels shod in summer tires) via Audi's trademark Quattro all-wheel drive. The S6 comes standard with Audi's Drive Select system, which gives the driver very simple or very granular control over the sedan's adaptive suspension system, throttle response, and electronic power-steering system. Quick settings for Comfort and Dynamic put the car in either its cushiest or sportiest modes, respectively. Auto lets the computer decide automatically how the S6 will behave based on your driving style. Individual is a driver-customizable preset. Like your suspension soft, but your throttle response dynamic? Here is where you can set it.
I didn't notice much difference between the Dynamic and Comfort suspensions modes. Both were sufficiently grippy, without compromising comfort. With the gearbox in its sport mode and the Drive Selector in its Dynamic mode, I did notice a dramatic increase in the throttle response and on-tap power. While the S6 was sufficiently damped against road noise, I noticed that the firm suspension allowed only a reasonable amount of road feel to be transferred to my spine. I also found that the electronic power steering felt a bit muted. This lack of feel, combined with the comfortable ride, doesn't inspire a ton of confidence in the car's suitability for sporty driving.
However, what the S6's handling lacks in feeling it more than makes up for in capability. It takes a lot to learn to trust the big sedan's computers, but once it earned my trust, I found that the S6's performance envelope was significantly larger than I expected it to be. The sport sedan is remarkably quick in a straight line, around long sweeping bends, and when tossed back and forth on a winding road.
The S6 is a top-tier level of the Audi A6 model line, so it comes darn close to being fully loaded out of the gate. You've got a sunroof, premium leather trim on the interior and S6-specific sport seats (with sweet diamond stitching and 12-way power adjustability on the driver's seat), four-zone climate controls, loads of LED interior illumination, LED-lit S6 door sills, and the full Audi infotainment system.
Drivers view the infotainment system via a motorized 7-inch screen that slides and rotates out of the dashboard, and interact with that system with a variety of physical controls on the center console. The most prominent is a large control knob that is surrounded by 11 large buttons with shortcuts to the various sections of the infotainment system, including navigation, telephone, radio, media, car options, and the main menu screens. Each of these sections features shortcuts at each of the four corners of the screen that are accessed with the four metallic buttons closest to the control knob. The control knob itself can be twisted, bumped in four directions, and pressed like a button to make onscreen selections.
That control knob can be used for everything from selecting the current audio source to inputting search terms for finding destinations. Farther up the center console is a touch-sensitive pad on which you can write letters with your fingertip when, for example, inputting an address or search term. Voice command is also an option for interacting with the infotainment system.