In the Gumball rally, people are flooring it through a bunch of countrys, wanting to get to there destination in first place (even though that doesn't matter). So if you were in the Mighty Bugatti Veyron 16.4 and you wanted to go and i mean GO. You would have to stop every half hour or less.
Fact: A Bugatti at top speed with a full tank will run out of gas in an estimated twelve minutes.
Iam guessing you are going to quite thats fast, but still.