The M3/4 did become heavier with time, but not by 110kg. I believe the original 1498kg weight advertized by BMW for the M4 was a marketing ploy, where it was for a complete stripper that more than likely does not exist anywhere in the world.
This is an interresting thread on the weight evolution of the F8X:
https://f80.bimmerpost.com/forums/sh....php?t=1365204