from what ive heard you still need an xbox live account to play PSO offline even. the box says live is REQUIRED. i think thats kind of busted myself. ive also heard that americans cant play with the japanese. take this all with a grain of salt tho since i dont have an xbox myself.
First off, Xbox does NOT have a more powerful processor than GameCube. Period. Don't even argue with me on this one. The only way Xbox's P3/Celeron hybrid beats Gekko is if you have flawlessly optimised SSE code everywhere which is a logical impossibility.
Second... I actually haven't played PSOe1&2 GC in 4-player split yet. But I have played 3-player and the frame rate stays at 60 in all but the most horrifyingly stressful scenes. Hmm. Oh well.