We've found what we believe to be the first set of spy photos of the upcoming RS 4 Avant posted over at MotorAuthority. Make sure to see plenty more angles of the car after the jump. MA notes the car is essentially A4 bodied with a unique RS-like chin spoiler, RS 5 wheels and brakes and suggests the car will be a high-hp version of the 3.0T FSI supercharged engine that should hit market in 2013 as a 2014 model.

So What Do We Think?
We believe this is an RS 4 Avant mule but our sources suggest some of MotorAuthority's details are incorrect. Originally we'd been told the RS 4 will share drivetrains with the RS 5 and that would be the high-rev 4.2-liter V8. A board level source told us you can't justify two different drivetrains for RS 4 and RS 5 so expect RS 4 to mirror RS 5... or rather the engine the RS 5 has when it gets a product improvement (PI a.k.a. facelift) next year. We expect they'll both keep the 4.2 high-rev though we wish they'd swap it for the 4.0T FSI.

The 3.0T simply isn't a quattro GmbH developed engine and so the likelihood of its use is slim to none despite what MotorAuthority says.

When will we see it? The new A4 is also due summer of 2012 as a 2013 model alongside the A5/S5/RS 5. The soonest we guess Audi will show the RS 4 Avant will be that time though it could very well wait a year as MA suggests. This remains to be seen.

We've rendered a few shots of the RS 4 Avant were it built in current pre-facelift guise and it can be seen below in Suzuka Grey and Ipanema Brown. It's worth noting though, the RS 4 won't be revealed until after the facelift.

The chances for the RS 4 Avant in America are actually quite good... better than A4 Avant and better than S4 Avant surprisingly. When the A4 facelift first launches the A4 Avant will disappear from the US market and be replaced by the A4 allroad. Audi of America thinks this will sell better and that's probably true if you look at Outback and XC70 sales versus their wagon equivalents. Still, the A4 allroad in the USA means the Avant body structure is still in market and that makes bringing the RS 4 Avant easier. Audi of America is quite serious about bolstering its RS chops in the USA and we were a fly on a wall during a conversation between quattro GmbH and Audi of America executives where they discussed "the Avant" and "the (RS 5) Cabriolet". We're hoping we see both but would settle for just the Avant.

Don't expect to see an RS 4 sedan. Audi AG used US numbers to justify the B7 RS 4 sedan (the only RS 4 sedan in Audi's history). The RS 5 was the smarter move here and with that model already in market, there's no business case for a sedan.

See more RS 4 Avant test mule spy photos after the jump. Thanks John S. for the tip.