According to one of our sources the next generation M3 sedan will not be powered by the feared V6 engine. BMW M has been experimenting with various engine configurations for the new generation M3, ranging from a naturally aspirated V8, twin turbo V8 and V6 setups to the much rumored tri-turbo inline 6.
Our source indicates that while the people at M pushed hard for the V6 because of the packaging and performance benefits the board shot it down. The board had a few reasons, namely the idea of a V6 in a BMW (let alone an M) and cost. The bespoke block and setup for the V6 would have required the car increase in price more than they were willing to allow and in the end the engine that fit performance (450 hp) and price-point best was the inline six based off the N55.
While this source has been reliable in the past we are still considering this a rumor as we do not have a second source and due to the significant amount of time before the new M3 will enter production in 2013.