After we got our first-taste of the new RS4 through a handful of leaked images earlier today, Audi has now officially pulled the sheets off the flagship model of its A4 series.
The RS4 makes its comeback as a station wagon featuring the same 4.2-liter V8 engine found in the RS5 models. The naturally aspirated eight-cylinder unit is good for 450PS (444bhp) at 8,250 rpm and a peak torque of 430 Nm (317.15 lb-ft) available from 4,000 to 6,000 rpm. That's a 30bhp improvement over the previous RS4.

Audi's seven-speed S tronic dual-clutch automatic transmission and quattro permanent all-wheel drive with up to 70 percent flowing to the front or as much as 85 percent to the rear with a default 40:60 ratio, transfer power to the road.

According to the German automaker, the RS4 Avant can accelerate from zero to 100 km/h (62mph) in 4.7 seconds and reach a governed top speed of 250 km/h (155mph), which can be increased to 280 km/h (174mph) upon request, while consuming less than 11lt/100km on average (21.4mpg US).

Like other RS models in Audi's range, the RS4 Avant features a revised chassis. Among other upgrades, there's a new speed-dependent electromechanical power steering, a taut suspension setup that lowers the body by 20 millimeters (0.79 in), and a new brake package with 365 millimeters (14.37 in) front discs. As an option, Audi offers 380-millimeter (14.96 in) carbon fiber ceramic discs with six-piston calipers for the front axle.

The RS4 Avant rides on 19-inch, ten-spoke forged aluminum wheels shod with 265/35-series tires as standard, but Audi also offers 20-inch wheels with 265/30-series tires as an option.

In typical Audi fashion, the RS4 Avant is subtly aggressive featuring newly designed bumpers, side skirts, a rear diffuser, a different front grille in a matte aluminum-look finish with a honeycomb insert, slightly flared wheel arches, a discrete roof spoiler and aluminum-look mirror housings.

Audi says that the RS4 is 20 millimeters (0.79 in) longer and 24 millimeters (0.94 in) wider than the A4 Avant, but 20 millimeters (0.79 in) lower.

In the cabin, we find a pair of sports seats and a flat bottom, multifunction steering wheel up front, along with carbon inlays on the dash and aluminum inserts on the door sills. Like the regular A4 Avant models, the RS4 offers up to 1,430 liters (50.50 cu ft) of cargo space.

After its world premiere at the Geneva Motor Show next month, the RS4 Avant will arrive in European dealerships in fall 2012 with a base price of €76,600 (about US$99,900) in Germany. No word on whether it will be offered in North America, but we wouldn't bet on it.