Reviews read by TheCarConnection.com were enthusiastic about the overall great performance of the 2008 Audi A6.
A choice of powertrains across sedan and wagon lines includes a 3.2-liter V-6 that generates 255 horsepower, as well as a 4.2-liter V-8 rated at 350 horsepower and available only in a sedan body. Power is transferred in front-drive models by a gearless Multitronic continuously variable transmission (CVT), which has been programmed so that it can be "shifted" like a manual transmission in seven stages. Models with standard quattro all-wheel drive, including the V-8 sedan, use a six-speed automatic transmission. There's also a high-performance S6 powered by a V-10 engine, which TheCarConnection.com covers separately.
As The Auto Channel explains, "two engines are available in the A6, a 350-hp V8" and a "255-hp, direct injected 3.2-liter V6." The Los Angeles Times recommends upgrading to the V-8, calling it "as state-of-the-art as a V-8 can currently get," with "equal parts power, composure, comfort and excitement." In terms of acceleration, Edmunds finds the V-6 a "little short on low-end torque," which is listed at "243 pound-feet." In contrast, the V-8 delivers "325 lb-ft of torque," enough for Edmunds to call the Audi A6 2008 "as smooth and potent as any eight-cylinder in the class." They conclude “neither will set the world ablaze with their acceleration, but these world-class engines manage to propel the A6 with more than enough gusto for most luxury buyers.” ForbesAutos says the A6 “is equally happy cruising on the highway as it is taking spirited turns on back roads. It's especially fun to drive with the optional V8 engine.”
Transmission gets the thumbs-up from reviewers as well. Edmunds says, “The 3.2 front-wheel-drive sedan has a continuously variable transmission (with driver-selectable shift points), while all other A6s come with a six-speed automatic transmission and the Quattro all-wheel-drive system.” The Los Angeles Times finds the six-speed Tiptronic automatic transmission "so well geared that the engine is barely turning 2000rpm at 65 mph." Cars.com remarks, “The six-speed automatic's shifts are almost imperceptible during leisurely driving, but become appropriately firm when the car is driven hard.” Kelley Blue Book notes that a "lack of a manual transmission option could be a turn-off."
According the Kelley Blue Book, the "Audi's famed quattro all-wheel-drive system gives the A6 a real advantage." ConsumerGuide agrees, declaring "AWD versions are near the top of the class for agility, grip, and poise," and adding that "the brakes deliver smooth, short stops." For performance, “We timed a 3.2 Quattro sedan at 7.9 seconds from zero to 60 mph,” Edmunds says. “As expected, the V8 is as smooth and potent as any eight-cylinder in the class and posts a 0-60-mph time of 7.1 seconds.”
“Quattro's downside, as with any all-wheel-drive system, is reduced fuel economy,” ForbesAutos reports. The Los Angeles Times notes "fuel consumption on the freeway can be as impressive as 26 mpg." ConsumerGuide points out "Audi recommends premium-grade gas for the V6 and requires it for the V8." The EPA rates the A6 at 18/27 mpg as a front-drive V-6 with the CVT, which no reviews seemed to encounter, and at 16/23 mpg for the sedan with all-wheel drive and the V-8 engine.
With any of the engines, the A6 lineup has a distinctly light touch to its controls, far from the hefty responses you'd get from the Mercedes-Benz E-Class or BMW 5-Series. The steering is deft and quick, the brakes responsive, and even with the less powerful V-6 engine, the A6 feels lighter on its feet than most of the cars in this class. “While the 2008 Audi A6's handling is softer than that of other top midsize luxury cars, it provides an excellent ride around town, along with predictable reflexes and precise steering through turns,” Edmunds says. "During high-speed cruising, the A6 provides a serene cabin and a confident feel at the wheel.” ForbesAutos observes the A6 “excels at isolating occupants from road irregularities while offering ample agility for more-aggressive driving.” “Handling is responsive and secure,” Consumer Reports finds, and “the ride is firm yet comfortable.” However, Car and Driver says, “Ride gets harsh with larger wheel options,” and it contradicts other sources when it reports “overly sensitive throttle and brakes as well as numb steering will annoy the enthusiast.”