>>49065483I didn't play through Colosseum in Japanese
I've played through it in English dozens of times so I don't really care if someone wants to call me a cheat, I bought the fucking bonus disc, that's the expensive part. I just downloaded a completed save file of Japanese Colosseum and put it onto a blank memory card using a Wii Homebrew GameCube memory card manager. You don't actually need a physical Japanese copy of Colosseum if you do that, but you DO need a Japanese Rom of Ruby/Sapphire and a Ruby/Sapphire save file that has beaten the Elite Four, but loading an English RS save file on a Japanese RS Rom works just fine.
All that said you'll need either a hacked Wii/Gamecube or an Action Replay to run the disc. Or just a hacked Wii with the ISO for the disc, IF you can find said ISO.