What kind of world do we live in where a 255-350 horsepower luxury sedan isn't enough? Answer: a most righteous one. Audi engineers pushed aside the A6's 3.2-liter V6 and 4.2-liter V8, opting to outfit the lineup's resident brute, the 4,486-lb. S6, with a normally-aspirated V10 borrowed from the Lamborghini Gallardo, albeit detuned for more mainstream use. Featuring 5.2-liters of displacement, direct injection, a 12.5:1 compression ratio and dual overhead cams, the 40-valve aluminum V10 boasts 435 horsepower at 6,800 rpm and 398 lb.-ft. of torque at 3,500 rpm (90 percent of the total torque is available between 2,300 and 6,200 rpm). That represents a significant jump over the last S6, a 2003 model, which drew motivation from a 340-horsepower V8. A six-speed Tiptronic automatic transmission with paddle shifters delivers the goods to all four wheels through the brand's quattro all-wheel-drive system which is rear-biased with a 40 percent front/60 percent rear torque split. Audi claims a 0-60 mph time of 5.1 seconds.

That time is thanks in part to the grip of 265/35 performance tires wrapped around 19-inch alloy wheels, which in turn are connected to a speed-sensitive rack-and-pinion steering assembly and multi-link suspension that sits 25-mm lower and is noticeably firmer than the A6's optional sport suspension. Furthermore, standard stability and traction control systems as well as front and rear locking differentials are employed to stay the course. A Torsen limited-slip center differential is also standard equipment. When behind an inattentive driver in traffic or approaching a gnarly 90-degree right hander, the S6's stout antilock braking system utilizes 385-mm front and 330-mm rear ventilated discs to slow things down in a hurry. Electronic brake force distribution and electronic brake assistance technology aid in the effort.