To say they have nicer or faster cars is a dumb statement. Not sure what Trumps ideas have to do with that.
My guess is Trump was repeating/butchering some information given to him regarding the Mexican drug cartels and the vehicles they use for human trafficking. Trump was probably embellishing/exaggerating the information to make a case for the wall.
However, Mexican drug cartels do have the money to buy and/or build pretty much whatever vehicle they want.
Google narco tanks.
Heck, they build
disposable submarines, for crying out loud. Google narco submarines. They make so much money that they just abandon the subs upon delivery of drugs, then find another way back.