Just some more info for you as well that I found :
The Skyline GT-R 'Nismo' was introduced on the 22nd of February 22 1990 with a total production of 560 units as required for the "Evolution" models regulation (over 500).
Its purpose is to homologate a number of aerodynamic changes used in Group A racing with changes including additional ducts in the front bumper to improve airflow to the intercooler. A bonnet lip spoiler to direct more air into the engine bay & an additional boot lip spoiler to provide more downforce.
The 'Nismo' GT-R was only available in Gunmetal Grey.