Ich hab zwar selber keine Ahnung aber ich kann ja mal schreiben was bei meinem Import händler steht:
Final Fantasy X International
+ Supports English voice, Japanese subtitles (game can be set to fully
+ New boss game, new abilites, summon battles
Final Fantasy X-2 International
Final Fantasy X-2 International + Last Mission is based on the US release of Final Fantasy X-2, with extra missions in the Yadonoki Tower, and bonus movie scenes not found in the original Japanese version.
Additionally the game has a new Monster Arena, in which you can battle with all the monsters and enemies from the game. You can battle against characters from Final Fantasy X, including Auron, Tidus, Seymour; as well as a new boss Emerald.
Final Fantasy X-2 International + Last Mission also includes a Final Fantasy VII Advent Children Trailer.