I have a DC header that uses a Honda Donut Gasket with a 51mm ID and 64mm OD which is 2.5OD.Im ordering a kteller catback and was planning to purchase a carsound cat as well but he wont weld the JDM 2.5" collector onto the cat. Will a Type R single o2 sensor cat mate up to the DC header and pass CA Smog?Getting a stock Type r car is cheaper than going with a Carsound and is supposed to be more efficient.