I read 2 days ago that PSO I and II is the one that the software has been designed for, but that recent support has been added for PSO III. I'm no expert, I'm just relaying information that I read somewhere else. If I were you I'd play it safe and get PSO I and II. But I also think that a Mod Chip is the best way for playing GC backups. EDIT: Here is the link that I'm getting my shit from: http://forums.afterdawn.com/thread_view.cfm/228876
When I modded my gamecube the only PSO that worked was PSO 1&2 make sure it isnt PSO 1&2 plus that version wont work and PSO 3 will not work either. Im sure that hasnt changed since iv modded my gamecube 6 months ago. The link you gave above says that only the Japanese version of PSO 1&2 plus and 3 work. I did some searching and found some support of that being true. so I guess if you have the Japanese version they will work.
