I'm pretty sure you guys know this already but there's another trick to bypass the "Modified PS1 detected" screen, which I believe is called the "swap trick" or something.
I don't know about other consoles, but for the PAL grey PS1, if you open the disc cover, there is a little circular button on the top right.
First, open the cover and insert a legitimate game. While the cover is still open, press and hold the little round button and turn the power on. I'm not sure at exactly which point this should be done, but after the initial two Sony bootup screens, while stilling holding down the round button, replace the proper game disc with the Japanese one. It should bypass the screen, and you can close the case and play the game.
It seems a little dangerous swapping discs while it's still spinning, but it works.
In other news, I sold my Wild Arms 2nd Ignition (as a bundle along with NTSC U/C Wild Arms + Wild Arms 2) for more than I got it for.
I r happy to rid myself of it.