I dont really know much about the g35 except that it is basicly a skyline(not to be confused with the GTR) and has the GTR drivetrain. So I cant say wich one would perform better then the other on dry pavement.
As much as I like the looks of the 350z, something about the g35 coup is just so... sexy in a classy way. Almost european IMO. So at the moment I would pic the g35 in a heartbeat.
I will be interested in any performance stats on these cars and how they compare.