you ought to get to a kart race meeting where they run the 250 nationals & see them in action. it's bonkers. the guys driving them are all bonkers. I've yet to attend a race weekend where at least one session doesn't get black flagged - the main straight at dunks is about 300 / 350 metres long, and these dudes are nudging 110mph buy the time they brake for turn 1.
absolutely insane. I was offered a go in one but I politely declined.
there's a guy running in the club champs that runs a 250 nat kart with a ktm 250 four stroke single - it sounds AMAZING.
edit: just watched the trailer - that kart looks pretty slow on public roads!