The driveshaft is CF. The individual to the rears are not to the best of my knowledge.
i meant the propshaft but everyone calls it the driveshaft these days
"power is routed to the rear wheels via a carbon-fiber driveshaft. Nissan says this special driveshaft is quieter and weighs 40 percent less than a comparable steel unit."
from here and i've read it elsewhere
http://www.edmunds.com/insideline/do/Dr ... leId=66816