Lets say in 10 years, 3D printing technology become so advanced, almost anything can be perfectly replicated. So I find some leaked car 3d file, I download it, I print the car. What current laws would I be violating? Civil or criminal? And what future laws can you anticipate?
Patent laws aside, having a printer big enough to print a vehicle or even parts of a vehicle to assemble would not be cheap.
Then you would have to go through the hoops of getting the vehicle certified as road safe to even drive it on public roads.
So having the machinery to print it, the resources to print it, the know how to assemble it, and the procedures to have it certified as road safe, would be enough of a barrier before folks would be concerned with patents.
In the us it isn't too hard to get a title for a kit car. It needs an inspection and emissions test in most states, but it's certainly possible and people do it regularly.