Originally Posted by swamp2
The CF roof is simply one small piece of the weight/CG engineering effort very effectively implemented by BMW. Not to mention a huge marketing/wow factor. A huge reason they did this was to address the concerns of typical M drivers about weight bloating and to claim M3 weight < 335i weight.
Good info. One note though... the E92 M3 weighs more than the E92 335. 1655kg (M3) vs 1600kg (335).
E92 335 Technical Specifications:
E92 M3 Technical Specificaitons: