Originally Posted by Antares
Carbon roof, trunk, hood (bonnet) and door panels should take away good 40kg (so a BMW engineer told me when I asked).
Apparently the price is still a trifle prohibitive.
Sounds like a real upper limit on what could be saved. The existing hood weighs 10 kg and trunk weighs almost 11. Doors are 18 kg ea. Throw in an extra 5 kg for a steel instead of the light E92 aluminum hood and you have about 62 kg. If you cut 66% of the weight (very agressive design) you would save right around 41 kg, almost 100 lb.