The ECU is wired into the speedo drive gear in the gearbox, it limits the speed of every Japanese car by cutting ignition/fuel when it reaches a certain speed(around 180Km/h or 50 metres per second) I know because I have actually programmed A LOT of Skylines(and other Nissans/Japanese cars) Search the internet for a 'Speed Cut defender' to remove the 180 speed cut and it is a electronic box wired in to fool the ECU into never reaching 180Km/h road speed signal. The Nissan GTiR RNN14 Pulsar also is electronically limited to 180Km/h
There is definitely not restrictor plate in the R34 GTR. There are TWO air flow meters with each one feeding each of the turbos. The airflow meters have wire screens on them to stop the sensitive components inside from being damaged but from the air flow meter to the turbo inlets, there are def no air flow restrictors.
The only restrictor is in the wastegate pressure line, which limits boost to the wastegates(via bost control solenoid) to give no more than between 8~10psi depending on what rpm your at. Feel free to post a picture of ANY R34 GTR and point out where the restrictor is located in the engine bay
Also, R34 GTR skylines do not need the front driveshafts removed to make them RWD only, just modify the wiring to the ATESSA 4WD transfer case. Removing the driveshafts actually makes the ATTESSA clutch packs fail but also, reduce the power output to the rear wheels as it is still spinning the 4WD transfer case. The R32 GTR's were awesome because you could pull a fuse and wire up a switch so you could change it from 4WD to RWD with a flick of a switch
PS: As a car magazine journalist(and mechanic) I can tell you do not believe everything you read in a magazine or see in a movie. We like to dumb it down for nOObs so they can understand things that are too complex for them to understand