odbII requires post cat sensors weather you have 2 or 12 so you logic there is flawed. I am not saying the pipe does not have cats. I am just not 100% possitive they are all cats. have you ever removed all 4 items to verify they are cats? the cali cars have 6 items in the midepipe. like I said I used to think this as well but someone posted in that there were not all cats. I should just go look at my old midepipe close and end all the speculation for sure. you could possibly be right but if you have never actually verified they are cats you are making an assumption.