How much of my car needs to remain before I switch out the VIN?

I was thinking about getting a certain car, but they have recently been banned in my state. But the ban is selective. They just won't register new ones.

So I had a shower thought today. How much of an original vehicle must remain before the VIN doesn't apply?

What's stopping me from say, taking the steering wheel from my car and putting it in another and keeping the VIN?