I'm guessing the Nissan guys are getting hit more for not paying import duty more than an "illegal" ( non DOT compliant ) car. ( RE: Not paying tax on the moon shine they are making. )

I wonder how the 25 year law addresses importing race cars built from a road car or cars built from scratch / body in white where a VIN doesn't exist.

A few years ago there was a small Mercedes high wagon / SUV for sale that claimed good title. This may have come in under " you are able to import one non conforming car in your lifetime. "

If you dig around the Kubota tractor web site, there should still be a blurb about how Kubota had a law passed " specifically " for them to ban import of Kubota brand gray market tractors regardless of year.

From a non Kubota web site
10 Myths about Kubota Gray Market Tractors | OrangeTractorTalks

Myth #1: Gray Market Kubotas are Illegal to Own
Gray market Kubotas are not illegal to own. In 1997 it became illegal to import Kubota gray market models into the United States. It is still legal to import gray models into Canada and many other countries. The General Exclusion Order awarded to Kubota by the US courts is to protect Kubota’s business interests in North America. The import ban on gray market models has nothing to do with their lack of reliability, performance or safety.

. . . . Kubota missed an opportunity to buy some goodwill. The right thing to do would have been to take those gray tractors in on trade or at the very least supported owners by offering parts and service. Build a relationship. Strengthen your brand. The import ban came about in 1997. For the last 13 years there are no more gray market models entering the United States. Eventually, the existing gray market models will die out and as they do those owners will likely not return to Kubota. . . . .