I think the profile picture that some of you guys have used to measure the vehicle's length with the 19" rims serving as measure unit has delusional proportions, hence you came up with an unrealistically short total length...
Here are a few other profile pics you can use:
--> These seem to be the F30's 17" type 394
--> Unknown to me but apparently 17" as well
--> M4 apparently on 19"
Maybe the measures will prove me wrong but I can't quite believe the F32 is shorter than the F30 or even the E92 (F30 is 4m62, E90 is 4m52 and E92 is 4m59)... unless BMW deliberately made the F32 less spacious than the E92 so that people looking for rear room upgrade to the 4 GranCoupé