Although that might look like an S4 Avant, our friends at Carscoop tell us to take a closer look at the heavily-blistered front and rear wheel arches. You'll see the same dark 20-inch alloy rims found on the RS5 Coupe, as well as a modified front bumper with different air vents to supply additional cooling to the engine.
Yup, according to Carscoop, what you're looking at is likely a heavily-camouflaged tester for the new Audi RS4 Avant. It's believed that Audi will make use of the same hardware under the hood as the RS5 Coupe. That means the RS4 Avant should get a naturally-aspirated 4.2-liter V8 hitting 450 HP at 8,250 rpm along with 317.15 lb-ft)of peak torque between 4,000 and 6,000 rpm.
Get more details on the hot Audi wagon over there.