long time no see but here's my current race bike(well,one of them)http://t.co/ehDxKE1FhJ
switching to discs with otherwise very similar components brought a weight penalty of less than 100 grams
frameset is superlight with 1600 grams for a 55 with fork, headset, small parts for mechanical shifting, seatpost clamp and extralite expander and topcap(frame 1,02 kg)
i don't have to mention the excellent stiffness because i'm already used to that from last years canti bikes.
i've done all races with wolftooth chainrings and that's also worked flawlessly.
switching to discs has been a lot of work for me but i've loved it from the first second.so much more modulation while you can always grab the hoods with much force.