With my Carbone 7, I think most of the lightening is with the frame and wheels (Mavic 32H GEL280s), although the SSC derailleurs are pretty weenie themselves, the'heavyish" Mavic 630 crank and "nothing special" Stronglight sealed bearing steel axled BB do cancel any of the RD/FD weenie benefits......amybe the new Look Keo Classic pedals help a little bit more.....
But I am still surprised with the completed bike weighing in at around 17.3 pounds (I'll confirm again tonight!)...........at least that's what my two scales have been telling me!

Chombi