As of January 1st 2009 all OBDI catalytic converters will be illegal

davidyan

^ CA does have routine inspections which includes a visual inspection plus tailpipe test. As long as your CEL isn't on indicating a CAT failure and they see that there is a Cat behind your exhaust manifold, I doubt you would fail the test given that the emissions would probably still pass the tailpipe. Do you know if the aftermarket cats have their brand stamped into the cat which might tip off the mechanic that its not stock? I.e, does it look stock?