Temporary Importation Permits for cars

Since 2012: Converted my FM3 to Temporary Resident in 2014 in Zihua and have been told by local immigration office that I must convert to a Permanent Residence this yr, 2016 and can do that locally. In fact, in 2014 I was given the option to get a Permanent card that yr. Did it all locally in Zihua. Perhaps it was because I already had a FM3 for several years, acquired in Denver, when I started the whole process in '96. Rules vary throughout Mexico, but perhaps to be safe than sorry, one should start in one's home country. But I will let you know when and if I attempt to get my Permanent card in November in Zihua.