Jackson Gurus-Whats the difference USA vs. Japan

[jerryjg]

Ive got an Solist XL MIJ Jackson. Its such a nice guitar, I really cannot imagine anything nicer.
I switched the Schaller out for a JT580 LO-Pro, which I prefer, and oit really plays like a dream and sounds excellent.
Aside from pickups ,which can be easily swapped) and the Trem(which also can be swapped out ( to an OFR or in my case the JT580) fairly painlessly, what are the big differnces between a Custom MIA vs. a MIJ Soloist?
I guess the quality of the wood for starters, am I right?
Select Alder would have to be far more impressive sounding than the lackluster poplar in my XL, no?
Is there a difference in the fit and finish or waht.Well, I mean solid colors.
I also guess that the necks are more deluxe.
Clue me in please. Thanks.