What's that you say? Can't afford one of those new V8 Ariel Atom 500s? Well, who says the only way to have an insane power-to-weight ratio with four wheels is in one of those trackday toy cars? They're barely streetable anyways. Just do what this guy did, and mount a Hayabusa engine on your go-kart. It may have a tooth-gnashing, organ-jarring ride, as seen in the on-board video after the jump, but it sure delivers all the thrills you'll want.