ECO CAT

[Rat407]

Well, since I had to go back into my engine and replace the broken oil ring that was causing all the oil useage I'm updating the exhaust. I have the MkIII down pipe, the one that bolts to the catalytic converter. Question is can I purchase any diesel cat for this or do I have to use the O.E. cat?  Due to emissions I have to run it or I can't get it inspected.
Thanks

[VWRacer]

You probably want to check with your NC's DMV, but even in California (with arguably the nation's toughest emissions laws) one does not have to run an OEM cat after 50,000 miles or 5 (?) years. Diesel cats may be different to gasser cats, but I'd be tempted to run a 2.5" turbo-back exhaust with a 2.5" cat in the correct position.