This video compares 3DS Rainbow Road on 3DS and Nintendo Switch, as well as a Wii Custom Track.
The custom track was made by ZPL, and it's part of Mario Kart Wii Deluxe v7.0, by FJRoyet and Deluxe Team!
Other places that you can find me:
Xbox: GruTheftAuto
PlayStation: GruTheftAuto
Steam: BronyCFW
Wii U: NotBronyCFW
3DS: 100660013099
Switch: SW838888934485
TikTok: @bronycfw