Nitrous and a modded JRSC won't be "legal" either.

I'm not too well accquainted with the California smog laws, but I believe that you first can go to an independent shop that does a tailpipe sniffer test. If you don't pass that test then you have to go to a smog ref who does all kinds of other more pain-in-the-ass tests.

The independent shops don't really look at the CARB stickers and such, do they? With pretty much any setup you should be able to keep tailpipe emissions low enough with a quality cat and good tuning of your fuel delivery.