DD, part numbers for Infiniti and Nissan are oftentimes very different, but for the same part. And most of the guys at Nissan parts don't know how to properly cross reference parts.
It would be very out of the norm, if Nissan created completely different suspenson parts for the 370Z. To keep costs low, Nissan has always shared suspenson and drivetrain components with it's Infiniti counterpart.
I have no doubt they will bolt on. But as for spring rates, they will be off...maybe better...who knows.
Just covering my ***...I havent test fit anything yet.