I'd expect same as other resident evil playstation games that JP version would not be allowed on a modded ps2 with driver 1.1 because the game runs abnormally faster than it should.

From what I understood, if his PS2 has the PS 1.1 driver it is not ok. if it has 2.0 driver it's fine I believe. So pretty much if it's a modded fat it's probably not ok, if it's a slim it probably is.

i'm pretty sure it will get brought up if your run is abnormally fast :)