[fragdude]

I think in CA they do both a "sniffer" test and visual inspection, depending on where you get your inspection done. Most companies will tell you if their product will pass the sniffer test, however if you go to an inspection station that is strict about the visual inspection part (even though its a bit harder sometimes on a boxster), you wont pass with anything but the muffler modified. It all depends on the station you go to. Some don't care, some will pass you if you pay them a bit extra.

Hope this helps