6NS is a new option that has been introduced along with the new navigation system that wil be on all cars built from April. Not sure what it does, but I'd guess it will be the same as the F30/31 as they will all share the same navigation. There was a thread in the BMW forum on Pistonheads about it if you're interested (the title was something about deleting sport suspension on an F25 X3 Msport).
Hope this helps.
2012 BMW X3 20d M Sport Manual - Sapphire Black/Black Leather - Winter Pack, Access Pack, Xenons, Panoramic Roof, Professional Audio, 19" 369 wheels, Grad Tint Screen, Storage Pack, Sun Protection Glass, Electric Folding Mirrors. Oh yeah, and a 2009 M3 Coupe Manual - Melbourne Red/Black Leather