From what I’ve read on one of the federal documents. This was awhile back… The R32/R34 Chassis can only be kept here in the US as a dedicated track vehicle and must be registered as a track vehicle, or some other reasons such as movie shoots/auto museums etc…
Once the car is imported the owner has 90 days to register the vehicle. If they see that the vehicle has not been registered then in some storys ive heard the vehicle has been taken and the owner has been given 30 days to deport the vehicle in their own means or they will crush it.
Im sure theres other ways aroudn it but its sad that they keep tabs on cars when theres so much more they should be keeping tabs on.
But in a nutshell from what ive gathered the car does need to be registered once its here, weather its track duty or some other means that doesnt involve trying to register it as a road legal car. I do know that when registering a vehicle as a track vehicle you must have a list of events/proof of attending the events in order to keep the car registered and here legaly