You should always use the official version of a game when speedrunning it. Mods, especially those created by fans, are usually not allowed in most established games. Romhacks are accepted usually as separate games, but it’s very rare to find a game that uses a modded version that is different from the official release.

Granted, there is no site wide rule for this, so I guess if you’re requesting a brand new game for the site you could use the modded version, but I would still discourage it if possible.

@Hollywood What game is it?