Know what this is?

Calling All Go-Kart Experts

Of course you do. It's an "Azusa Fun Kart", and apparently it's a popular base model. I'm what you'd call a go-kart noob, I don't know much about them, but I'm a young person with a summer ahead of me and I'd like something to goof around on (I am easily amused). Unfortunately, most kits like these sell for over $500, without engine.

Does anyone know if there are any similar, comparable kits that sell for less? And do these types of chassis hold up when given engines more powerful than the stock 6.5 HP?