Audi made a habit of building the most powerful version on its A6 model also on the station-wagon variant.
And the RS6 Avant was a proof.

The RS6 Avant is the epitome of a “factory sleeper”. Nobody would think that the big station-wagon barge in front of you would disappear into the distance in a second. But some clues could tell the others that under that big, heavy, car there was a supercar engine. The clues would be the big 20” wheels behind the flared wheel arches. On the front black grille surrounded by a chromed rim, there was a red and silver badge which said RS6. But most of the people saw the rear, where big two oval exhaust pipes were exposed.

Since the bodywork was a large station-wagon, it had plenty of room for five plus a minivan sized trunk. The front bucket seats wore the RS red-silver badge on the seatbacks. The upholstery was leather and Alcantara.

The platform featured a computer-controlled suspension. The shocks and spring settings, as well as the entire elastokinematics of the four-link front suspension and the trapezoidal-link rear suspension, had been adapted to the high level of performance.

But the heart of that sleeper was the big, twin-turbo, V10 engine under the hood. It was the same as in the Audi S8 and Lamborghini Gallardo, but since the RS6 was meant to be driven on normal roads more often than its Italian brother, it had around 400 specific parts on it that were not in the Lamborghini.