i can't remember what it's japan twin is, maybe the cima or leopard, but the m30's over here came with the vg30e (same engine as the 84-89 300zx). they only came with an auto if i remember correctly. you could probably make it a pretty sweet car by dropping in a vg30et with the 87-89 turbo 5-speed. that would be fun. if the car is the leopard's twin then they had the vg30det in there which had bigger head ports than the vg30dett over and sports 255 hp and 255 ft lb of torque i believe. that would be a very awesome swap!
here is the Nissan Leopard. It's an 86. i'm not sure when the body style was different but this car did have the vg30det. it pulled around 240 something horsepower (185 kilowatts if you would like to convert it over).
Its the Leopard. In 1993, the two door Leopard became a 4 door J. Leopard Ferie that was known as the J30 in the USA.
The M30/Leopard came with the VG30DE found in the NA 300ZX Z31 series. All US M30s were AT while Japan had this engine, the turbo version, and a 2.0liter turbo engine though I don't recall exaclty which one.
As for engines that can fit in the M30/Leopard:
Now, some engines will need custom motor mounts and other tweaking to be made to work, but they all will fit. I have seen every engine listed in an M30/Leopard.
Here is a cool link for those interested in the M30: