My tags are going to expire soon and I need a Catalytic Converter for my car. I own a GSR swapped 93 Civic Sedan and It is straight piped from the headers and connects to a muffler at the end. I bought the car already swapped and straight piped. Could I get some recommendations for a Catalytic Converter that will pass California Smog Check?

 

You have 3 choices,
1) install the OEM catalyst which is at the header, with the large print etching numbers visible
2) install a catalyst down the line that was on some civic models to match your current piping, but you may fail the visual as it will be obvious that the installation is not as specs... so
3) contact a referee and ask what need to be done to pass smog... which is rather intensive, you will need documentation about the engine purchase, because the engine number does not match the one associated with the VIN of your vehicle , it can be done

https://bar.ca.gov/Consumer/Referee_Program/Referee centers are centrally located within certain community colleges throughout California. To find a referee center near you or to schedule an appointment, visit asktheref.org or call (800) 622-7733.