What differs between the Cervelo S5 and S5VWD Looking at the Cervelo S5 series there are two different models but the Cervelo page offers no mention of what differences are.. could someone enlighten me? Looking just at the framesets is there a difference?
They are different frames, with the VWD being lighter than the normal one. It is claimed that other properties (stiffness, comfort, shape) are the same, though. 

This thread, in particular the post by em3, point to the following links from Cervelo: a,b.