I'd have to say Golden Boy. He's just more well traveled and experienced and could dish out quite the whoppin', being a nomad and all.

Onizuka has the power of immunity through misfortune, the most powerful immunity of all.

I was about to type Onizuka but I forgot that Kintaro knows kenpo...

That's actually kind of hard to answer.

I think no one would win. If anyone had an advantage it would be Kintaro though.