I played Mario Kart 8 and Mario Kart 8 Deluxe and when I noticed the names of the staff ghost profiles, they seem to be the same CPU Miis from Wii Sports Club and Wii Party U. Plus, I discovered their nationalities.
Within Mario Kart 8, several courses utilised anti-gravity, which allows for racing on places that normally won't be drivable due to gravity, allowing for more uniquely-designed courses. The mechanic also has the perk in giving a slight boost when racers bump into each other or one of the posts...