BMW may begin straying from its long held tradition of equipping its M models with rev-happy, naturally aspirated engines. According to a source speaking with Automotive News, the twin-turbocharged 4.4-liter V8 currently equipped on the new X6, could be stroked out to 4.8-liters and fitted on future Ms, including the new M5, due out in 2011. The twin-turbo'd 3.0-liter inline six found in the 335i, 535i and entry-level X6 proved that BMW has the chops to create highly efficient and eminently entertaining blown mills, and there's no doubt that significant tweaks to the turbocharged V8 could boost power levels over the stock mill's claimed 407 hp, to take take serious aim at Audi's 572 hp RS6.

[Source: Automotive News – Sub. Req.]