Originally Posted by aajami
I highly doubt that BMW would use anything but the same engine across the entire F8X platform.
The only wrinkle that I would expect in the development of this engine would be to see it in the X3M before it made its way into the M3 or M4, but that doesn't seem to be happening either.
Not so far, although there is still a chance we'll see it this year:
I think I also remember SCOTT saying mules should be out testing in public any time now, though I can't find a post to back that up. Still, it would seem unlikely to see it arrive before the F80 M3 since those mules have been out there for some time now. But perhaps the X3 M mules are simply better disguised or just too nondescript to have drawn much interest or attention.