I havent found a clear answer to this, but I do remember reading the revised 427 rear spring were the same length on both the Z and the G35 coupe. Can anyone confirm this is true or false? I know for a fact the earlier unrevised rear springs between the Z and the G35 were different lengths (G35 about a 1/2" longer). Im looking into swapping the revised rear springs in place of the unrevised but I like the lesser drop the G35 coupe rear springs give.

 

There have been a few accounts of them being the same length. Luckily for you, the evidence suggests that the 350z got longer revised springs that are the same length as the coupe springs and not the other way around. You should be able to swap out the unrevised g35 springs for revised 350z/coupe springs and have the same ride height(possibly slightly higher due to the higher spring rate compressing less at rest)

 

Perfect, that makes sense. Thanks for clarifying.