I recently bought a used Mexican-plated car. It's a 1987 Suzuki Samurai that was imported in 1997, and I do not pay tenencia. I was also told "ten years", but I'm not clear if that applies to the age of the car or to the length of time since it was nationalized. If you buy a Mexican car, you'll need a Mexican driver's license and insurance, but both are inexpensive and easy to obtain (at least in Baja California Sur).
(This post was edited by morgaine7 on Jan 1, 2008, 8:49 PM)