The 2013 Audi A6 returns reasonably good gas mileage whether it's equipped with the turbocharged four-cylinder engine in A6 2.0T or the supercharged V-6 in A6 3.0T models.
In front-wheel-drive 2.0T models, you'll have to endure Audi's continuously variable transmission to get the best 25/33-mpg ratings. But in 2013, for the first time, Audi is offering 2.0T models in quattro all-wheel-drive guise, with the eight-speed automatic. Those models earn 20 mpg city, 30 highway--1 or 2 mpg better than the 3.0T.
But even with the 3.0T and quattro, it's not bad; the supercharged, direct-injected V-6 powerplant and its standard all-wheel drive deliver 19/28 mpg.
Otherwise, the A6 doesn't quite hit the high-mileage mark reached by some of its rivals, as there are no hybrid or diesel models. They're on the way, however, as soon as next year.