I have a uas one piece chromemoly.
Found that it is slightly noisier at low revs, due to gearbox noise being amplified through the tube.
Vibrations in the center tunnel area at speeds over 85kph.
It is 4kg lighter than a two piece.
Big difference with putting a one piece on a GTR compared to a GTS-T/300ZX is:
GTR does not have a slip in spline which goes into the back of the gearbox, it is bolted to the output shaft on the transfer case.
All models are bolted at the diff end, the GTR is bolted at both ends.
GTR two piece has the main slip joint at the center bearing area to absorb forward/aft vibration from the front universal joint, other models use the front slip joint.
Ths is what I have found with mine. I'd suggest a carbon two piece similar design principles to stock setup if you want less nvh.
Just my opinion,
Cheers.