Is it a RWD, FWD, or AWD???

Depends on model, GTR, GTST.

AWD or RWD.

Haha, FWD?! No way.

The R34 has a torque splitting AWD system, when the ECM sees fit it is a RWD mainly when going in a straight line with no tire slip. It switches to AWD for grip in cornering and for leaving the line without excessive wheelspin.

As mentioned above for the GTR the GT,GTX, GTV,GTT r rwd setup with an hicas setup.
Whilst the GT4 version is the lesser powered engine than the GTR but has the AWD setup.
No skyline is fwd.

The GTR & GT4 have the Altessa setup.

ATTESA E-TS is Nissans advanced four wheel drive system which features in the Nissan Skyline GTR & GTS-4. Conventional 4WD systems have the car locked into 4WD all the time, grip is greatly improved, but more under steer is produced to that of a rear wheel drive car. ATTESA ET-S was designed by Nissan to give the best of both worlds, the result is a predominately rear wheel drive car which transfers torque to the front wheels as the rear wheels start to slip.

The ATTESA E-TS system uses a 16bit microprocessor that monitors the cars movements at 100 times per second to sense traction loss. Three G-Sensors mounted underneath the centre console feed lateral & longitudinal inputs in addition to this throttle position, wheel speed, & boost pressure, r measured & calculated by the ECU. When slip is detected on a wheel the system directs the torque away from that wheel to one that has traction, up to 50% of power can be delivered to the front wheels if needed. The Nissan Skylines engine & braking system r great but its this system that sets it apart from other vehicles.

ATTESA ET-S has improved dramatically with every skyline model change from R32 through to R34. Some people who want more from there Skyline have found major improvements by installing a torque split controller. Usually they come with 10 different adjustments which r selected dependent upon conditions & driver preference. The article in this link describes how a custom made controller was made for a R32 GTR, great improvements where evident.

Diagram.

http://nissanskyline.6te.net/img/attesa2.jpg

Skyline is RWD.
Skyline GT-R is AWD.

Ok, DO NOT LISTEN TO DCECIL, listen to tricky because he does know what he is talking about, he only copies and pastes on here because there are Skyline questions ALL the time. He always the question and then posts additional information for the person who asked. Do you or have you ever owned a Skyline dcecil?
Just curious.