This is a great compilation of the DLC for this game, but the tracks do not have any metadata, and they do not play correctly in iTunes. They play fine in Windows Media Player, but iTunes scrambles it and doesn't sound right.
Whoever recorded this did a terrible job. There's a lot of skipping within each song that it just becomes unbearable. You need to find a better quality for each of these soundtracks. And it's not just the Mario Kart 8 DLC, it's ALL of the Mario Kart 8 soundtracks on here.