I run mine pretty high (360mm front, 350mm rear) because of the loads when towing. Plus the handling is excellent for such a big car like this anyway. I have bilsteins, whiteline springs and sway bars from sydneykid
Could no doubt run 10mm lower without issue....but like any skyline chasis if you go too low you are going to stuff roll centres, get too much camber, get bad bump steer, and bad angles on cvs and driveshaft.