That's not something you expect to see.
With a combination of luxury, capability, usability, and performance, there's a lot to like about the Audi RS6 Avant. They respond well to tuning, too, as you can see in this video. The previous-gen example goes flat out on the autobahn and goes so fast that the speedometer stops operating.
In stock form, the C7-generation RS6 Avant has a twin-turbo 4.0-liter V8 making 552 horsepower (412 kilowatts or 560 metric horsepower) and 516 pound-feet (700 Newton-meters) of torque. The tuning for this one allegedly pushed the output to 690 hp (515 kW or 700 metric hp) and 693 lb-ft- (940 Nm). The tweaks include removing the top-speed limiter, too. An Akrapovič makes the V8 sound fantastic.
The autobahn is fairly busy during this run, so the driver has to make a few unsuccessful attempts before finding an open stretch where it's possible to push the wagon to the top speed. This provides lots of opportunities to hear the great noise from the exhaust, though.
When the road is clear, the RS6 accelerates effortlessly to about 180 miles per hour (290 kilometers per hour). From there, the speed increases more slowly. Something interesting happens at an indicated 324 kph (201 mph). The speedometer shuts off and spins back to zero. The car keeps accelerating, though. According to the GPS, the Audi hits 198.2 mph (319 kph) before the driver starts slowing down. This is an impressive speed for a vehicle that's still able to haul a whole family and carry all of their stuff.
While the C7 RS6 Avant was never available in the US, the latest-gen came to the American market. It comes with a twin-turbo 4.0-liter V8 that's good for 591 hp (441 kW) and 590 lb-ft (800 Nm).