A BMW source has announced that the future M models may come with turbo-boosted engines. Until now they were coming with high-revolution, naturally aspirated engines.

The first one will be the next M5 that will debut in 2011. It will be powered by a twin-turbo V-8 instead of a naturally aspirated V-10.

"Variations of the twin-turbo, 4.4-liter V-8 that powers the X6 premium SUV are on the test stand and generating "400 kW (536hp) and more of output," an insider said.

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