They race them around here. They truly are an “open” tech type class of karting that is growing fast. The local track here went to A hard tire right rear and still need new tires every 3 races. better then 1 race, I guess.
Motor wise its A toss up. the CR500 is FASTER on the bigger tracks with lots of maintenance.$2-$3000
The 450 less so but when they go bang, they tear themselves up. Motor run $4,500-$11,000 from Joe Gibbs.