Also check with the local used car dealers. Many times, they bring cars down from the US on a regular basis and will haul something else down for a reasonable fee.
The rules have changed since the "good old days"! The market for used cars from the US is pretty much done.
Option #3 “Permanent Import” (Nationalized Vehicle)
Permanent imports are regulated by and require a permit from the Secretary of Economy, but there is a special provision for used vehicles that can be imported without a permit. These vehicles satisfy the following rule: they are exactly 10 years old from the year of import and are manufactured in NAFTA countries. For example, in 2010, cars built in 2000 can be imported permanently without a permit if manufactured in the U.S., Canada or Mexico. Either with or without a permit, the procedure for permanent importation has to be done using a customs broker. The importer can hold an FM3 or FM2 visa or be an inmigrado or a Mexican citizen.And it is my understanding that they have changed the rules yet again, and that imported cars are now subject to annual renewal fees (instead of being tied to the FM3 as previously) of about $200 USD.

Since my car was not manufactured in a NAFTA country, I will never be able to put Mexican plates on it.
tanstaafl.