Is there any time difference in the language of the game rt wise? I know it don't really matter for ig time.

I think (correct me if i'm wrong moderators) it is just a couple mili-seconds faster if you do the Japanese version. I really don't notice a big diffrence

The Japanese version is 3 minutes faster on RTA compared to the English version. IGT is the same for all versions. The actual fastest version would be the Chinese version but that version is unavailable to us atm

From what I remember, I think JRP has said English is fastest for IGT, yes?

Eagle confirmed it's half a second.

Some of the clips that are only doable in the English version could potentially save a bunch of time, but they're not really practical outside of tool-assisted runs. So the main difference is the room right before you grab diffusion missiles, which is bigger in the JP version and therefore you lose about half a second of IGT in that room playing on JP.