I posted on this forum the point emphasized at the Town Hall meeting about individuals with the Permanent Resident card not being able to have a foreign (ex., US or Canada) plated car in Mexico as a town meeting participant, not in any official capacity. You would need to find out from the appropriate Mexican agency (Aduana?) about importing a car made in Japan. It is my understanding that only cars made in the US or Canada (members of NAFTA) can be imported. But I'm no authority on the topic.
I did ask Adam Smith to speak with Mexican colleagues about providing the immigration requirements clearly in English. It is our responsibility to follow the law, yet it is not easy to understand the law or to get accurate information. There are websites that discuss the regulations, including yuculandia.comhttp://yucalandia.com/2012/11/08/updated-mexican-immigration-rules/
Such websites try to share accurate information, but these are not necessarily "official" sites. And the laws get interpreted differently in different places by different people.
Perhaps we can use this forum to share sites we find particularly helpful.