BMW has quite openly stated its intention to rival the 911 with its many levels of power and track focus, so I would totally expect M8, M8 Competition, M8 CS and/or M8 CSL, ranging from 600-625ps to 700ps.
I'd love to see the M8 CS/CSL get this type of OLED tail lights which BMW has showcased, just like the M4 GTS/CS did: