The problem is the car ENTERED the country under the wrong pretenses to begin with, which means it shouldn’t be here, which is why they have the power to seize.
It’s not like you can go out and get a Skyline or any sort of grey market car right now and just say you won’t register it, they won’t let it into this country unless you have a predetermined reason for it to be here (such as racing) or it’s entering in parts that don’t qualify as a car.