We thought throwing a detuned version of the Lamborghini Gallardo's V10 in the Audi S8 and S6 was a brash move on behalf of Ingolstadt, but news from World Car Fans is that the next RS6 will receive a turbocharged version of the 5.0-liter V10 producing between 520 and 550 bhp. We previously thought the RS6 may get the Q7's top petrol engine, a 4.2-liter FSI V8 tuned to 500+ horsepower, but it would be strange to give the top A6 model two less cylinders than the S6. Still, this V10 makes 520 horsepower without the help of a turbo in the Gallardo, so it still seems strange to detune the engine and slap a turbo on it to increase the power back up to a level that can compete with the BMW M5 and Mercedes-Benz E63 AMG. Either way, Lamborghini can't be pleased that a high-performance saloon and wagon from Audi will soon be pumping out more power than its entry-level exotic supercar.

[Source: World Car Fans]