Stock Catalytic converter is: --2 catalytic converter pipes --Part number to order replacement from dealerships & Mechanic shops, or online store is seen in this video. --Different catalytic pipes can be used, but in some states like CALIFORNIA, its illegal to use Aftermarket parts; if it has not been tested to work as good as original Factory parts. Or if it simply just configured different "looks different". --Google your STATE government website for law, or call your Car Inspection shops, police officer.