Normally, any spy shots having to do with Audi's RS series involve large wheels, huge fender flares and low-profile tires. This potential prototype for the Audi RS7 Sportback, however, appears to be going incognito under standard A7 skin.

As for what's underhood, the latest speculation suggests that a twin-turbocharged 4.0-liter V8 engine will be in use, producing somewhere around 550 or 600 horsepower. This power will be managed by a seven-speed dual-clutch gearbox and sent to all four wheels via Quattro all-wheel drive. Expect the production car – with the normal aggressive RS fittings – to debut at the Frankfurt Motor Show this September.
[Source: CarPix]