It's been a while since we last spied the new F80 BMW M3. Set to be christened the M4 upon launch after the new M3 sedan takes a bow, the new name apes the distinction between the BMW 5 Series sedan and 6 Series coupe. The prototype's quad exhaust gives the model away as an M car, which although was at one point to be powered by a V6 turbo will instead have a traditional in-line six layout as a throwback to the E46. The new models are expected to be powered by a twin- or triple-turbocharged 3.2-liter straight-six unit.

These should manage in the region of 450 horsepower (a 30hp increase on the current model), combined with vastly improved fuel efficiency. Expect the new M3 sedan to debut at the 2013 Frankfurt Motor Show, with the M4 coupe to arrive sometime after the release of the new 4 Series, perhaps as late as 2014.