OK, so the bike definitely feels lighter with the C24s on there. Also, the ride with the C24s is a lot smoother than with the fulcrum 3s... This is probably because the Shimano wheels are carbon. The carbon wheels definitely make a different sound when up to speed. Kind of cool. In terms of responsiveness, they're about equal in my eyes. The Fulcrums still look nicer to me, but the Dura Ace is nice in a subtle sort of way. I threw on some Enve skewers too and lost another 65 grams with that simple upgrade. The bike feels super light on the road and stops on a dime too. So far, the bike has shed a little over a pound...