Originally Posted by BMW86
I'm confident the M2 will be a 6 cylinder. It has to be a step up from the M135i or at least share the same platform. It wouldn't surprise me if they reused the same N55 engine from the M135i with a different tune and give it the usual M treatment as they have done for the E82 platform. Main differences will be widebody, LSD, M suspension, quad exhaust and M badge. This on its own merits justifies its value, imo.
My money is on this bet. The next M2 will very probably be a around 350-360 hp (N55) engined car with enough M technical and design cues to make it differ from the rest, a la 1M vs. E82 135i. There is no practical reason why they don't go this way, unless they are already developing a very efficient and special 4 cylinder turbo to be used in cars like M2, Z2 etc. Unless I hear reliable rumours about that speculative engine, I am with BMW86's bet.