its a damn sexy but expensive factory option nismo oil cooler kit.
i dont know if you can get them anymore? i remember for example - seeing them advertised in a HPI magazine a few years ago and the price was around $5500 supplied (full package - vents, piping, tubes and cooler - etc), but not installed or painted. i probably still have the mag somewhere, i might be able to scan the ad if it would help you.
i've got one on my car and apart from mine, i've only seen one other GTR here in australia with the kit (well, that one only had the vents.. the cooler got flogged on the boat on the way over). they are a bit more common with the UK delivered GTR's, but i read somewhere that the ratio is still something rediculous like 1 in every 100 has it.
i think the extra vents make the car look alot more agressive. i've attached a more few pics for you.