just got back from the j-book store. i saw that the jdm 15 nismo had a black front bumper decoration where the ones we saw here had red. and the side pieces were more like the 13-14 without the silly red lines. it looked pretty good. even if that's not the actual 15' nismo, one can change the pieces and make the car look pretty nice.
official release in japan august. and roadsters are discontinued at least in japan it said for 2015.