Playing mm on WiiVC is extremely laggy, and audio is choppy; no matter where i go in the game. Does anyone know how to fix this?

PAL version has no lag, however isn't compatible with kz

If you have a PAL wii, you need to change your wiis video mode to NTSC with homebrew in order to play the US and JP versions of the game. There's a guide for that pinned in the softmodding channel in the discord.