what's the average price of a rear diff swap out??
I think this would be a great mod, the 370z is a little sluggish exiting a sharp turn in second gear, this would help put it more into the powerband.
My only concern would be drivetrain wine/noise. I've done this swap before on my last few mustangs 4:10's and the drivetrain noise went up considerably. Maybe the gears weren't set right.