Originally Posted by mlhj83
Don't think BMW has ever released structural info regarding the CF roof apart from weight. However, a little logical assumptions can be made. First off, the CF roof isn't a significant part of the roof's structural integrity in terms of support upon blunt impact, neither is a steel roof - it's the underlying cross beams, roof rails, A, B and C pillars. What the roof will do however is protect against intrusion of external matter, and this regard, the CF roof should do better than the steel roof, as the CF roof is thicker, stiffer and the fibre itself will be better at resisting punctures than a steel roof - CF has higher shear strength than sheet steel.
Also, another interesting feature of the M3, the front and rear bumper carriers of the E9X M3 is made out of carbon kevlar, which evolved from the E46.
Separately why wasnt a CF roof available on the Sedan, Cost?