I've been searching for the code for a while now.
I've found some but they don't work.
My CRC is F0A31EE3.
Does anyone know of a working pnach
or codebreaker cheat for this
version?
http://cheats.codetwink.com/ps2/view/4456/ has XP multiplier at the Misc codes page. But since the OP stated have searched and didn't find working ones, I suppose that's because the game's version/region.
I don't have that game so I can't say anything about it by the CRC alone.
Why would you want the xp code? Considering if you max out you level in the beginning you won't be able to learn any skills from the parasites considering they are learned at a certain level. It would be better to just max your hp or something. Or it could be like Xenosaga and you can put 99k xp but you will only gain 1 level.