Bro, unless you are already connected there it is fucking stupid to do business there. Here is a recent scenario that I encountered:
I was at a farmacia that I had frequented for years. I went in and inquired. He brought out QV shit. He was to bring it to me (i will stop there). Well, when we left to walk for the border, judicial police stopped us from walking and made me go against a wall to frisk me.... I had no gear with me, so they did nothing. But, if i had stuff with me It would have been game over.
When people say that you can bring anything there, but you cant bring it back, They dont know wtf they are talking about. Mexico is a corrupt place with a political system that is dependent on blackmail and bribes. If you want mexican gear, there are plenty of great domestic sources that actually cost less than you would pay there, ie stallion..