Originally Posted by TheOtherDave™
I'm not busting balls, but that's one heck of generalization...
To pass the California Smog visual inspection, all the aftermarket parts on the vehicle must have CARB E.O. Numbers. The only exception is the cat-back exhaust (but it must not be louder than 95 dB(A).)
If the part doesn't have an EO number, you fail the visual inspection, regardless of what your emissions are.
To pass the actual emissions test, you'll clearly need a functioning cat converter. Be warned, few things kill a cat converter and oxygen sensor faster than leaded race gas.
True, true...make sure the CARB EO number is actually for your car too. You may have a smart ass tech who looks up the number to make sure it is not from another kind of car, that just happens to fit yours.