Well I've got the magnaflow y pipes with cats and the rear ones are reading fine still. Hell the driver's side walker is fine. There was no oil or anything at the connectors and I ordered the good walker ones like all the brits rave about. It was almost out of the 90 day warranty. There was a little soot on it but nothing to be concerned about it's just making me crazy BC when I redid the heads, all new injectors and everything and I only run premium fuel (chevron or shell) and she purrs like a kitten. I'm about ready to plug both of them and let the ecm do is factory fuel trims. Anybody else running them like that

 

Well sending the old one off today and will report back when I get the new one in and installed.