With the OEM Calsonic radiator I had water temps nearing 100C just on a spirited hill climb.
With the Koyo 53mm radiator it never exceeded 95C on a track day with ambient temperatures at around 20C and the bottom tank was only lukewarm.
I'm running mine with the OEM clutch fan and shroud, Nismo 1.3bar radiator cap and OEM 76.5C thermostat (can't justify 100$ for a nismo one when OEM can be had for $30 from Nissan).
The build quality is fantastic, and fitment was a breeze. All the mounting holes lined up perfectly with the OEM shroud. All mounting points lined up perfectly with the radiator support panel/top mounts. I just made a little extra clearance at the areas on the chassis where the corners of the radiator was situated so there was no metal/metal contact (crucial) - bit of hammering here and there.
Also I cut my hoses about 1cm shorter so that it wouldn't kink when fitted.
It is also a good idea to check for stray current in the cooling system before/after you change the radiator.
