Answered my own question.
A Hoon is someone who drives too fast or recklessly.
It's also a verb. To hoon is to drive fast or recklessly or to show off i.e. peeling out, doing doughnuts, drifting, or engaging in illegal drag racing.
The word came from Australia, and is thought to be a shortening of hooligan. Hoons are a problem in parts of Australia, and some localities have anti-hoon laws.
A Donk is a Chevy Impala with 20-inch or larger diameter wheels. Derived from the Impala logo, which is supposed to resemble a donkey, but I don't see it.
Dubs are 20-inch diameter wheels, from double tens (twenty). I thought dubs came from "double u" (W), short for wheels, but what do I know? Not much, apparently.
From Urban Dictionary and Wikipedia.