Taking Drums to Mexico?

I'm moving from the US to Mexico (my wife is a citizen), which means spending a lot of time trying to figure out the bizarre customs/import rules. One of the more dificult issues is bringing my drumset(s) with me.

I have an acoustic set and an electronic one. Of the two, the electronic is a lesser worry, as it packs much smaller (although that's no guarantee I can get it across the border, at least not without paying a fee). But I have no clue about getting my acoustic set across. There seem to be these odd rules about the number of musical instruments you can bring and their total value, and besides just being a sucky rule (who would take musical instruments to Mexico to sell them? They make most musical instruments in Mexico!) it's very unclear what they count as "an instrument", like is a whole drumset a single instrument? Does value depreciate? What about used drums, for which I have no receipt?

Has anyone else tried doing this?

If worse came to worst I could leave my kit behind and buy a cheapo one there. But I'm sure everyone understands I'm attached to my kit, so I'd prefer to bring it along.