Mine is the often forgotten older original version of the 300ZX with a single turbo bolted to the older SOHC 3.0 V6 VG30ET. It was classed as a Z31
The later Z32 twin turbo 300ZX was released in 1989, and is the version most people associate with 300ZX
Mine (actual photo's):


Z32 Twin turbo:

The Z31 was always a single turbo. They added DOHC heads to the base block for the Z32 and bolted a further turbo to the other bank in the process. They then changed the engine model to VG30DETT.
These engines are bullet proof. Some people in the US are running them up to 1000BHP, with restrictions as to what they are allowed to change to make the power challenge harder. Not bad for a near 30 year old engine design. I, however, don't plan to get anyway near that figure. I can easily get to 300BHP with no internal modifications at all. Just bigger turbo and upping the boost. With what I am planning I can foresee an easy 350 BHP and 400 BHP isn't too far out of the way. Time will tell.
Yes indeed I have a manual gearbox being the Borg Warner T5, rated as the strongest box fitted to the 300ZX. That same box was also fitted to the Sierra Cosworths.