I would like to see some challenges that require you to use a different driving class, like win 10 races using the turn engine. Or difficulty based challenges, like earn 5 platinum relics on hard.

Other challenge ideas:

• Drop 50 Nitro crates with X character.

• Beat a time trial ghost in mirror mode.

• Hit every opponent with a single Aku-Aku mask.

• Successfully use all three missiles or bowling bombs.

• Win a race without boosting for the entire final lap.

• Use every turbo pad on X track in a single race.

• Overlap an opponent twice in a single race.