My guess (and it is only a guess):~$750 for the complete kit (bolt, carrier, CH etc.). I figure the initial offering will be in kit form, with individual parts available down the road.
Of course, since it's FN, the kit will only be available once every 93 days, and only between the hours of 2:43 AM-2:57 AM CST.
Me, I'm skipping the upgrade and going whole hog...either another 17 in the NRCH flavor or a 20 NRCH...I can't decide. But being as I just blew this year's firearm budget, I have plenty of time to decide. Anyways the thought of buying and outfitting another SCAR doesn't inspire urgency.