Its reportedly easier to change the clutch with the engine out, then separate the motor/gb when out of the car.
Bungs has a thread somewhere in our tech articles detailing how he changed the clutch in his FWD U12 TRX in his garage. It didn't look easy to me, but it is do-able. However, the AWD's have two mounts holding the gearbox onto the chassis on the passenger side, the FWD's have one.
Will you be sending the car to a workshop or doing the work yourself?
The clutch IS the same as the S14. The throw out bearing is not. Get a genuine GTiR bearing from nissan.