2000 I30 with California Standard Catalytic Converter

[dansals]

One of my catalytic converters is bad. I purchased my car in California, but live in TN. The repair place has told me that I have to replace it with the same California emission standard part from the dealer and cannot replace it with a direct fit converter or it has to potential to mess up my cars computer system and cause my CEL light to continue to come on. Does anyone know if a direct fit part is acceptable or do I have to use a factory part?