I looked into buying a new car in Canada for use and ownership in the U. S. The requirements are daunting and expensive. There is no guarantee that any party necessary in the chain of those involved will be willing or able to assist and even if so, to do so on the buyer's time schedule so that all events occur in the necessary order. The manufacturer has no interest in stealing sales from one country for another. Safety and emissions issues are different, and apparently trivial issues will become large for a bureaucrat or insurance company employee. Licensing title for out of state is one thing, but out of country is another. Transport and import tax must be arranged in advance and the decision at the border on any one of the many pieces of paper necessary is final and cannot be appealed. Warranty is for the country where delivered to dealer and not elsewhere unless waived in the case of military moves and others of that type. Brokers may be able to assist in this effort but one must REALLY want the car and be willing to wait. And wait.
My research led me to conclude that unless the car is 20 or more years old then the effort was not worth the risk. These 20+ year old cars follow different rules and the manufacturer and original dealer are obviously out of the picture. However the insurance, licensing, title, transport, border tax payments and other issues must be considered.
Edit: if one lives on the border, such as Buffalo, then may-y-y-y-be it could work as the owner could take the car to Canada for all repair and service. The rest of the story remains the same, sadly.