Originally Posted by RVGRINGO

"My question is: if an American expat (living in Mexico on a FM2 or 3 and a U.S. driver's license) may buy a used or new car in Mexico, does ownership of this Mexican vehicle reduce their ability to bring in one (additional) vehicle registered in the US?"

You may own as many Mexican vehicles as you wish, but only one from the USA, Canada, etc. No matter if you own a mexican vehicle or not, you are restricted to ONLY ONE, foreign plated vehicle per person as long as your immigration status (FM3/2) remains valid. You must eventually remove that vehicle from Mexico, even if it doesn't run, when your immigration status is about to lapse. When you get your 'importada temporal', you sign a bond to that effect. There are fines and penalties if you violate that bond. Selling a foreign plated car in Mexico is prohibited.