how to tell if catalytic converter is legit or not?

Hi i recently had my cat robbed took them 2 mins i need to know where about on these cats the marking are as i intent to buy a aftermarket one and try and put these marking on it and install it so hopefully these thiefs come back and try and take the cat again so i can catch them as im working on something to catch them in the act if this works we will all be able to sleep well at night thank you

 

What your government requires is about as far as we gotten in this research... There have been some DIY tests to show that aftermarket cats do clean the exhaust just as well when the vehicle is not moving. But the tests for how well they clean the exhaust when the cars is in normal use is less clear. You can follow this situation as it develops here: Prius Cat Theft Tracking | PriusChat

 

I don't think you need to go to that much trouble. The thieves are too stupid and probably would not know a genuine OEM from an aftermarket.