To play Booster Course Pass, you need a Switch + official DLC or NSO+Expansion Pack. There is no “better ROM” – but buying it supports the developers and gives you online play, leaderboards, and future updates.
This is the heart of the "better" argument. Because the BCP tracks were ported from Tour , modders have created that only work on ROMs (not on standard Switch hardware without hacking). mario kart 8 deluxe booster course pass rom better