How do people in Cali pass smog when they upgrade their cars? I've seen people going catless and a few HPF e46 M3's and I want to know what they do. Do people just have the ability to return the car to stock or am I missing something else?

This goes for any car that is heavily modified in Cali, including Evo or Sti's with upgraded turbos and exhaust, boosted S2000's, or American cars with SC.

Thanks!!!