Ever consider that this could be because it would be unprofitable to manufacture these in the US due to certain regulations so they are doing it in Mexico to help the bottom line
A lot of GM plants are in other countries and the price of Labor is the main reason. They quit building plants in the US in 2003. They pay un skilled workers 32+ an hour to put a screw in a truck. Some of the workers are grateful but the Majority of them swear they are overworked and under paid.
I remember when we launched the Colorado/Canyon in Shreveport in 03, we worked a few months of 6 10 hr days (9 hrs on 1st shift) and some of the fine union folks actually had shirts made that had the Plants turnstiles behind Prison Bars on them with "GM state penn" written underneath. They all got together and decided to wear them on a certain days and wore them often.
There is also a lot of "made up positions" for the Lazy folks that get hired on and cant be fired. they just screw around enough until they find themselves in one of these cush positions. these include "Problem Solvers", "ergonomics investigators" and "committee Men". They also were paying janitors 32.50 an hr with full pensions. couldn contract it out because they were "Union Brothers" and deserve the same pay.
Gm isn't American Made. Some of the vehicles are Assembled in America, but the most parts come from local suppliers that get the parts from foreign countries and the few parts GM does get direct come form other countries also. Id say 10% of the vehicle is made in America.
The number I remember in 05 was 6K off of every vehicle sold by GM went to retiree pensions and benefits.