Audi continues to chase BMW and Mercedes-Benz in a seemingly relentless race to technological leadership, and in that it's doing very well. Simultaneously, as other automakers are breaking out to vary appearances a bit depending on the size of the vehicle, Audi is whipping its sedan lineup into fighting shape with a uniform look and more evenly divided price points. That shape-up works fine for the more attainable A4 and the social-climbing A8, but somehow the A6 ended up with a conservative look and middle-son status.

With the 2013 Audi S6 and its 420-horsepower turbocharged V-8 engine, seven-speed S tronic gearbox, and performance upgrades, you definitely add excitement. But for any of the A6 family, the sheetmetal is more formal, and far less distinctive and inviting, than that of the beautiful A7 fastback. Even though the cockpit of the A6 and S6 are clones of the A5