Was thinking. How strong is this composite carbon? I know for a fact since i stripped my brera completely many times that the bumper stiffner rail is also quite heavy
well, that bumper stiffener is heavy part and good candidate for weight reduction, BUT ...
please be aware that with change from metal to CFK you would definitely change the behaviour of the crush zone. I know that main impact energy absorption elements of structure are undulated fwd posting tunnels, but that bumper stiffener is connecting them and is dissipating energy from one side to other, thus absorbing itself a lot of energy.
CFK is very strong material but is kinda brittle when collapsing, meaning that is not that good for energy absorption elements. that is the reason why is not used for bullet proof wests.
for that element you would be much better making some combination of the CFK and Kevlar (aramide fibres). Kevlar is exactly good for energy absorption and is used massively for that purpose. BUT, Kevlar is not light material, which brings you back the weight. plus you need somehow (for your safety) to calculate those impact energies and with layup organise same absorption rates (and that is the science for itself).
with whole honesty, unless this car is for track only and you are adding additional cage inside the cabin, would recommend you not to touch that bumper stiffener.
but will follow your thread religiously