Few intermediate luxury sedans can boast the same versatility as the Audi A6. This car comes with your choice of three engines: a 252-horsepower 2.0-litre 4-cylinder turbo, a 240-horsepower 3.0-litre V6 diesel and a 333-horsepower 3.0-litre supercharged V6. And then there's the sportier S6, which comes with a 4.0-litre V8 twin-turbo that delivers 450 horsepower.