ok, you are from CA and obviously have good experience in that state. The topic starter wants to buy a post 1974 vehicle and is seeking our advice. So if CA is so incredibly emissions conscious and any modification to the catalytic converter is considered 'tampering', is everything controlled by the service centers that would install the exhaust system? Is it the responsibility of the State or local police to inspect your post 1974 vehicle for a proper carb certified emissions exhaust? I believe NY is following California. Other states are starting to as well. It would be interesting to hear from a New Yawka' or other New England state that has recent experience with regards to a post 1974 passenger car registration and inspection.