Re: Mexican vs. Jap vs. US made strats.
As far as I know, the only MIMs that were laminated were the 90's models with a transperant finish. Since they were poplar, and poplar tends to have a green tinge to it, they'd laminate an alder top and bottom on.
To tell if it's a laminate, look at the back. If the dark part of the burst is the same width all the way around, it's not a laminate. If the dark part of the burst widens to cover the whole belly groove, it's a laminate. They did that to cover up the fact that there was no laminate in the belly groove.
I have a '99 MIM that's routed for S/S/H, I heard they stopped the swimming pool route in the mid 90's sometime.
As for the difference between the MIA and MIM mades, when a load of wood comes in, the best wood goes on the MIAs, and the left over goes on the MIMs. Does that mean the MIMs get only crap wood? No. Most of them are made out of wood that's just fine. The MIAs get better quality hardware and more time is spent finishing them (cleaner fretword, better setups, ect). The MIM pickups suck, so if you get one plan on replacing them. Also, judging by the quality of the solder work in my MIM they hire monkeys to do it. The solder work on my MIA is top notch.
As far as playability goes, I like my MIA and MIM guitars equally, and they both get similar playtime.
From what I understand, Fender Japan is a separate company from Fender USA. So their production methods and materials may vary. Also, (again, from what I understand) MIM's are made in the US, just assembled in Mexico. The MIA's have better quality control than the MIMs.