A talk about performance can't overlook weight, especially an extra 150 or so kg.
A set of good coilovers fixed the F87's "skittery & unsettled" handling over rough roads and together with PS4S's there isn't midcorner understeer.
Won't be so easy for a G87 owner to shed weight
Having run a set of the G80 PS4S Star spec 275/35/19 fronts on the back of my M2 it would seem BMW's answer to the weight is a soft compound tyre that sadly gave half the tyre life (12-13K km) of a generic PS4S on my F87, put them on a heavier car on 'driving' roads I'd expect even worse wear.