Audi's S performance magic has been applied to its latest S6 and, for the first time, the shapely S7 hatchback.

While most other luxury automakers create mid-level vehicles by simply installing an upgrade motor in the base model, slapping on new badges and calling it a day, Audi takes a more comprehensive approach with its S-badged cars.

Positioned between the automaker's standard "A" and hard-edged "RS" offerings, the S models combine sport-focused suspensions, extra technology, additional luxury and unique exterior treatments with the requisite up-level engines. The result is often an overall package that feels more cohesive - as well as more special - than the competition.

As Audi has recently redesigned much of its S-model lineup, we decided to spend some time behind the wheel of the new S6 and S7 to see if the automaker still has its mid-level mojo working.

Fraternal twins

While the S6 sedan is all about understatement, the S7 "four-door-coupe" demands attention with its fastback roofline and wide hips. Clearly the latter is the aesthete's choice, while the S6 appeals to more traditional types and those looking to fly under the radar.

Underneath their distinct exteriors, the S6 and S7 are essentially mechanically identical. Both are underpinned by VW Group's MLB platform and utilize a new 4.0-liter twin-turbo V8 that serves up 420 horsepower and 406 lb-ft of torque from 1,400 to 5,300 rpm. In comparison, the next level down in both models' engine hierarchy is a 310-horsepower, 325 lb-ft of torque supercharged V6.

Paired with a quick-shifting seven-speed dual-clutch automatic transmission, the forced induction eight can propel either car from zero-to-60 mph in a claimed (and likely conservative) 4.5 seconds. It sounds throaty and feels strong, with plenty of mid-range grunt and the kind of high-speed passing power that befits a car from the land of the Autobahn.

Despite the powertrain's performance, fuel economy is respectable 17 mpg in the city and 26 mpg on the highway. A cylinder deactivation system that turns the motor into a 2.0-liter V4 at highway speeds helps keep consumption down, as does the extensive use of lightweight aluminum. While their basic unibody structures are made from steel, about 20 percent of the S6 and S7 is aluminum, including the suspension and body panels.

The S6 weights in at around 4,250 lbs. - roughly the same as the smaller, V10-engined last-gen model - while the S7 is about 100 pounds heavier due to its hatchback and slightly larger dimensions.

Inside, the appointments are above reproach as per Audi tradition. Flowing lines and premium materials are the predominant themes, with S-specific touches like sports seats with diamond-pattern stitching, aluminum pedals and (optional) carbon fiber trim helping to set the cars apart from their more quotidian A6 and A7 siblings. We were impressed by the craftsmanship throughout, and particularly with a trim piece that runs along the top of the dashboard -it's constructed from a single piece of carbon fiber, rather than several separate sections.

The S7 offers more cargo space thanks to its hatchback design, although the S6 counters with an extra rear seat and additional headroom courtesy of its more formal roofline. Both feature Audi's new Connect system - which includes in-car internet connectivity along with Google Earth imagery for the navigation unit - as well as Audi Drive Select.

Drive Select lets the driver adjust number of different system settings, including throttle response, steering effort and shift calibration, by selecting from four different modes - three of which are pre-set, with fourth allowing for changes to each individual setting. Drive select also controls the air suspension and adaptive damping system - both of which are unique to the S models

Helping both acceleration and handling is Audi's quattro all-wheel-drive system, which here provides a 40:60 front/rear torque split and comes equipped with a crown differential that can send up to 70 percent of output to the front axle or 85 percent to the rear. Also part of the package is a rear torque vectoring system that works to hold the driver's intended line in turns by apportioning available torque between the wheels.

With all that technology on hand, both cars can handle nearly any road you throw at them. Tighten the suspension up via Drive Select's sport mode and head for a turn, and the chassis remains composed while the vectoring system keeps things neutral by shunting power to the outside rear wheel. It's an excellent recipe for conquering curves, although the experience feels slightly artificial - it's the computers, not you, that do the work, although that may be just what some luxury buyers are looking for. Those seeking a truly engaging drive should wait for the upcoming RS variants (although only the RS7 is likely to make it to the states).

As one would expect given the high percentage of shared components, handling differences between the two cars are infinitesimal, which brings us to the subject of price. At $79,695, the S7's base price is $6,900 more than the S6's $72,795 MSRP, so there's a significant sum to be paid for the extra style. The S6 is more expensive than its BMW 550i xDrive and Mercedes E550 4Matic rivals, while the S7 commands more than the Mercedes CLS550 4Matic but undercuts the BMW 550i Gran Coupe xDrive by about $10,000. However, both Audis feature more standard equipment and feel like sportier, better-rounded rides than their competitors.

Leftlane's bottom line

With an appealing blend of indulgent luxury and accessible performance, the S6 and S7 show that Audi is very much at the top of its S game.

Though not comparable in terms of power or joie de drive, the duo nonetheless manage to capture something approaching the sense of occasion and uniqueness of a BMW M or Mercedes-Benz AMG model at a mid-level price.

2013 Audi S6 base price, $72,795

2013 Audi S7 base price, $79,695

Words and photos by Nat Shirley. Some photos courtesy Audi.