Just finished my build up last night, most parts will stay as-is, but some were just what I had on hand to get the thing rideable.  I got the frame and wheels from Peter right after he left I-Play and had barely named the other company but pulled the trigger anyway.  I have previously built up a no-name carbon road bike as well and it has held up fantastically to some pretty awful race conditions.  On the 057 frame, I went with this option since I race downhill as well so I ride a little harder than most, and the 256 just looked to not have that much material on the seatstays.  But the internal cable routing for the front derailer looks very tempting to run a stealth cable dropper post, so I may upgrade to that later.  During the build, all of the cables pulled thru nicely with the guides that came in it, although they are not really needed since the lines are all sleeved for the full length anyways.  everything lined up nicely and fit properly.  The spec is like this-
057 frame
the larger width hookless 29er wheels with novatech hubs (forgot the model #)
xt rear mech with shadow plus
xt cassette 10-spd
slx cranks with raceface wide narrow ring
Avid juicy ultimate brakes
Bottle cages from speed carbon
reba RL fork
Thomson 50mm stem
race face sixc carbon bars
extra mech hangers- because you know, smashing into things