In that case, Vanellope & other Sugar Rush racers should look like a combination of the proportions of the Sugar Rush 64 models plus the pixelated cartoon expressions of Frogun & Megaman Legends, to make them look cuter.
And also, a Sugar Rush with that graphic style for that time, it would have been a more than competent game compared to Mario Kart 64 and Diddy Kong Racing.
True, the gameplay would also probably have a few elements of arcade racers of the time like Daytona USA, Cruis'n, San Francisco Rush, Ridge Racer, etc
I don't think I'm quite qualified to make it myself yet, but maybe I will in the future, I'd have to familiarize myself more with the design philosophy of racing games though, actually I have been thinking about doing my own version of TurboTime at some point
