There have been aftermarket speaker setups to emit the "choosh" sound of the wastegate opening marketed to the ricer crowd for years.
No, he's using it to refer to Asian vehicles (and colloquially, people immersed in the culture surrounding them). It's a bit racist, but more of a subcultural epithet.
I think the "rice" word (aside from the racial connotations) came from the stereotypical first modification being an absurdly large exhaust to try and lower the frequency of the typically smaller, higher-rev'ing / turbo'd Asian engines.
A noticeably large cylinder shoehorned on to the back of your car? Rice cooker.