iT'S ON THE ENGINE BAY TAG.
The nissan owners club is a good place to find cheap parts
http://www.300zx-twinturbo.com/cgi-bin/manual.cgi
autozone
conceptzperformance.com Z1motorsports.com
Try Zczr.com
One can find a Nissan 300ZX at a local used car dealership and at many websites. Among the websites are Autotrader, eBay, Amazon, Cars for Sale, and Car Gurus.
Purchase a Nissan 300ZX Twin Turbo by looking through local classified ads. The local paper, Craigslist and Auto Trader are good places to find a Nissan 300ZX Twin Turbo. Also, visit your local car dealerships.
Parts of the Nissan 300ZX can be purchased at a Nissan dealership. One can also purchase the car parts online at Car Parts, Slick Car and Auto Parts Warehouse.
http://www.importworkshop.com/files/manuals/nissan/z32-factory-service-manual.pdf
It is easy to find a repair CD for your zcar on the auction sites.
The key code for a Nissan 300ZX can typically be found on a small metal plate that is attached to the driver's side door jamb or in the owner's manual. Additionally, if you have the original key, the code may be stamped on the key itself. If you are unable to locate it, contacting a Nissan dealership with your vehicle’s VIN can also help retrieve the key code.
The Nissan shop manual has a complete wiring diagram, they can be found on e-bay.