Many reviewers noted that the exclusive "Founding Member" suits and kart parts (like Donald Duck's special wheels) are purely aesthetic and don't affect performance. Grind Persistence:

For the Nintendo Switch specifically, the Ultimate Founder’s Pack is the best way to play the game technically. Because the game has large texture downloads and aggressive microtransactions in the free version, buying the Ultimate pack removes the initial grind and provides the smoothest gameplay experience right out of the gate.

Even with the "Ultimate" head start, the game's core loop still relies heavily on a daily "mobile-style" grind for character shards and materials. Ultimate Founder's Pack Ultimate Pack Instant Unlocks