Are there actually two different assembly plants? Or do you just mean that 2/3 of the components in the Taco are Texas-sourced? I researched it years ago when I was shopping for the truck, but I've forgotten the specifics long ago. I do know that every single Taco I've looked at on the dealer lots showed a final assembly location of Mexico on the window sticker (Tijuana if I remember correctly).
And I agree completely on the aftermarket support. The Tacoma is like the Wrangler of pickups. I haven't done any offroad mods to my Frontier, and don't intend to, so it wasn't a factor for me.