Million times in my mechanic career (over 35 years). Anyway, I did welded up universal cat in 2006 or 2007 (bought it from Summit, I think it was Walker brand). This cat was not 50 state legal emission when the cat converter law in California was started in 2009. My van passed a smog check at Test Only station with illegal cat, smog inspector didn't take a look at it, cuz I told him that I'm a licensed smog technician at the Repair & Test station. I have to send my van out to the muffler shop to replace a new OBD-II cat converter next year for a smog check. I tell you any cats from Summit or other stores, won't sell them over California. Dammit.