No Music ModReplaces all music files with the same copy of 'silence' so that you can play whatever music you want on top of it! Sound effects are not affected :)
Not permanent - so you can go back to the original soundtrack.
Installation* (for Cemu, we don't know about Wii U mod installations, sorry!)
1. Unrar in your graphicPacks folder in the main Cemu directory.
2. When you open up Cemu, and before launching the game, go to 'Options->Graphic Packs' and tick the 'Mario Kart 8->Game Mods->No Music' box.
To uninstall, simply untick the same box.
This method of installation is what makes the mod temporary and reversible, by not overwriting the files.
GLHF have fun =)