Its not so much Jap vs US versions as it is early vs late release.
The earlier release had an extra audio sample in the attract mode that said something along the lines of "Play that shit like you just got your motherfuckin..."
Ah! I knew it had to do with audio! Good to know.
So I figure the early release would be the Jap version? I have both and about to plug them in to find out.
Glad madman is not around or he'll say "use search function noob"..........................