The 2013 Audi A6, in the 2.0T Quattro version, is capable of returning 20/30 mpg in city/highway, which isn’t enough compared to the BMW 528i xDrive.
The guys at Car and Driver have recently stumbled upon the EPA official fuel economy figures for the 2013 Audi A6 2.0T Quattro, which are showing that the luxurious sedan can return 20/30 mpg in city/highway, but these figures have improved thanks to the addition of the new optional 2.0 liter turbocharged and direct-injected four-banger unit and to the ZF automatic transmission, because the previous numbers were showing 19/28 mpg in city/highway on the standard supercharged V6 engine used in the Audi A6.
The 20/30 mpg in city/highway fuel consumption might seem in the favor of the 2013 Audi A6 2.0T Quattro but the fact is that the similar BMW 528i with xDrive all-wheel drive is able to return 22/32 mpg in city/highway, along with 22 more horsepower. But there is a catch here too, because the BMW 528i with xDrive is 5,400 USD more expensive when compared to the 45,295 USD which you will have to pay to get the 2013 Audi A6 2.0T Quattro. You decide which one is best.