In the 80s I was bringing Porsches over from Germany. It was pretty easy back then, basically documenting the needed changes. With many of the German cars you would get documentation from the Mfg that the body shell complies with USA regs. Both Mercedes and Porsche just make one bodyshell for all the world. I then had to change doors and add bumper reinforcements. Then change the lights and add seatbelt and brake warning lights and all was good. Vehicles made after 1983 need roll over protection added to the fuel system. Emissions were done with waivers where everyone is allowed one vehicle of non compliance.
I never brought over a Japanese car since I could not read their for sale adds.
This was so simple it got abused, bad.

The proper method now is a shop gets certified to bring in a specific brand and model of vehicle. Convert it to conform and it is free to travel the country.
Other out of country individuals bring in vehicles on their non USA passports. These vehicles are to leave with them, many do not. I can list a few that are now track use only or run under false papers.

Some states are easy to register non conforming vehicles in. They want a bill of sale and do not need a certificate of origin or a title. I expect down where that Pajero is this maybe the case.

In these states you can assemble a vehicle from parts and register the car. Up here that is done with the early EVOs. The EVOs get shipped into Montreal and disassembled there.
Customs has a good take on this, do not ship all the parts in the same trailer on the same day <img src="/forums/images/graemlins/smile.gif" alt="" />