A guy I know with a 2019 F90 M5 CP did 100-200 in 6.87 seconds. A verified run on 4x4 Sport Mode.
A stage 2 FXX M5/6 should easily do better than this... I agree with
RPiM5 that the only thing that matters is Vbox/Dragy numbers. These numbers truly show what a car is capable of doing.