I suggest really thinking it through before going with a c/f seat post. If they break (not unheard of at all) I hear it's painful to remove the c/f shards from your arse! I built a lightweight (21 lb) c/f hardtail a few seasons ago and my buddy who works for Mavic recommended against a c/f seatpostNice Cannondale. Is there a thomson aluminium seat post mounted? I would definitely change it with a light carbon fiber seat post. Also the saddle is not the lightest. There's a lot of potential to save some more weight.
But anyway really nice bike, I like the look of the lefty fork!