I read recently in one of the monthly magazines that there is a new V12 for the 7-series, and that BMW will use it as a model for the design of future 4 and 5 liter V8s to replace the 4.4 liter. The M5s are always cancelled after 3 or 4 years, so, at that time, there will not be a need to keep smaller engines in the M3 and the 540. It is easy to see the M3 getting a new 4 liter V8, and the 540 being replaced by a 550 with a new 5 liter.