Everyone's attention may be centered on the start of the 2011 Frankfurt Motor Show, but spy photographers are still hard at work capturing images of future models as they test their way into perfection. This week's captive is the new Audi RS4 as it takes some hot laps on the Nürburgring.

The new RS4 Avant prototype caught testing revealed some new lights and a new grille which will highlight the upcoming facelift for the full A4->ke1087/S4->ke1088 range. It also features big air intakes on the revised front end, wider fenders, and massive oval exhaust pipes.

Now comes the power. If you live in the United States, chances are you don't really care about the newRS4->ke742 Avant, either because it hasn't been confirmed for the US market or because Americans still have this "thing" about not liking wagons. For the latter, may we remind you that Audi likes to test their S variants in wagon form before expanding to the more traditional models, so listen up. Audi->ke14 has two options for the new RS4's engine. Their first option is to use the same 4.2 liter V8 with 450 horsepower found in the RS5, and the second is to down-size to a twin-turbo V6 which will deliver about the same amount of power. We're placing our bets on the V6 only because automakers have to focus more on fuel economy and if Audi can get the same amount of power and provide customers with gas-saving efficiency, that's what they are going to do.

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