[Olefin]

Now if you are looking elsewhere to build up the Mexicans

Brazil would be operating M41 Bulldogs - they had 340 of them - they did have a lot of indigenous APC's that Mexico could have bought

Argentina would have the TAM - that is a pretty good tank and they would have been producing them right around the canon time frame but I dont see them parting with more than 30-40 of them at most

Israel would have Super Shermans, Egypt older Soviet equipment, and again you have the French for sure since they had already sold so much to Mexico

Personally I think Mexico could have pulled off the invasion with the equipment they had - they caught the 49th out of position, other units spread all over the place and their main opposition at the start would have been MP units (and not combat ones most likely), National Guard units that were most likely logistics and transport companies pressed into being border guards and riot control units, and local police and militia units.

Given the state of the US by mid 1998 if they had had a large tank force the US probably couldnt have stopped them short of Kansas and Arkansas and San Francisco

And while the equipment they have isnt breakthru equipment, their army isnt that kind of army - they train to fight insurgents and rebels and riots - so most likely they didnt send their troops into battle riding those APC's they had or use tanks as breakthru units - instead they used the APC's to transport men to where they could be discharged but without exposing the APC's to direct fire (i.e. doesnt matter if the US has M203's or Mk19's if the infantry gets deployed way out of their range) and they may have used their tanks and armored cars as mobile artillery - i.e. putting the 90mm cannon on the ERC-90 to use in a support role for infantry

and considering they would have had access to men who were trained to get into and out of the country much of their offensive would have consisted of getting around US units using that knowledge, making our guys fall back to avoid being surrounded - i.e. the Spartans at Thermopylae went down because they got flanked and forced out of the pass, not becauses of the frontal Persian assaults