Nothing in the world of four rings is more exciting than a new RS model, and the anticipation over the new RS7 Sportback is killing us. This recently spied test mule seems to indicate that the RS7 isn't quite production ready, but expecting to see it at the Frankfurt Auto Show in September would be reasonable. What leads us to believe that an RS7 heart beats in this A7 body? The quad exhaust would be the first clue.

Of course, that could just as easily be an S7, but the presence of those massive brakes suggests that this is something a bit more special. The fog lights have been removed to allow whatever engine has been shoehorned in under the hood to breathe better. What that engine might be still isn't known, but rumors of a Lamborghini V10 have been replaced by rumors of a twin-turbo V8 that will produce something in the neighborhood of 600 horsepower. Photos courtesy of gmotors.co.uk