I have the 159 c2btx snowboard from 2012 which should be almost the same as the split.
The split has a different base then the board . Its TNT
Also if it is current year then its c2btx not c3 like the regular board.
On the fall line thing. once the nose points downhill the flex of the board gets faster as it goes. it accelerates carrying speed.
Its nimble around trees b/c its softer torsional and stiffer front to back or longitudinally.
basically it very fast and mobile taking out all the bumps.