Ever since the reveal of the latest-generation Audi A6 in late 2010, performance fans around the world have been holding their breath for the announcement of a new RS6 sledgehammer.

Today we have the first spy shots of a prototype for the new RS6 Avant wagon, which was spotted while conducting some high-speed testing at Germany’s notorious Nürburgring circuit.

The latest shots finally confirm that a new-generation RS6 is in the works, although it remains unclear whether both a sedan and Avant wagon will be launched or just the wagon.

Audi has chosen to launch its latest RS4 model exclusively in the Avant wagon bodystyle and it’s possible that the same will occur with the RS6.

Of more concern is the uncertainty of whether the RS6 will land in U.S. showrooms. However, given the recent introduction of the TT RS and soon-to-be launched RS5 in the U.S., not to mention the success of rival models like the BMW M5 and Mercedes-Benz E63 AMG, it’s likely the new RS6 will come too. If it does, expect it to be pegged as a 2014 model and available as a sedan.

The RS6 is often described as a wolf in sheep’s clothing, or the car supercar-owners use as their daily drivers. That’s because the last version packed a powerplant worthy of cars from the likes of Ferrari or Lamborghini--a twin-turbo V-10 with 580 horsepower and 479 pound-feet of torque--but had the body of a stately sedan or wagon.  

The new RS6 is expected to continue that tradition, albeit with a smaller V-8 engine due to stricter emissions regulations and increased environmental concerns. Power will likely come from the same twin-turbocharged 4.0-liter V-8 engine found in the 520-horsepower S8, albeit with output turned up even higher. Final figures should match or come close to the 580-horsepower figure of the previous model.

The lighter aluminum-hybrid body of the 2012 Audi A6 on which it’s based means performance should eclipse that of the previous RS6. Expect 0-60 times in the low 3.0-second bracket and a top speed of 180 mph or more, the latter with its electronic speed limiter removed, of course.

In addition, the new RS6 should also feature a host of new performance technology including an S tronic seven-speed dual-clutch transmission, launch control, adjustable suspension, quattro permanent all-wheel drive, torque vectoring, and Audi’s latest crown-gear center differential. This latter feature can vary the distribution of power between the front and rear axles immediately, smoothly and over a wide range.

On the outside, expect the usual RS paraphernalia such as pumped fenders, chunky 20-inch wheels, carbon ceramic brakes (either standard or available), and two big oval exhaust tips integrated in the rear bumper.

Look out for an official world debut of the 2014 Audi RS6 in the first half of next year.