Looking for recommendations or experiences with replacing the exhaust manifold with the 2 cats on it. The current manifold has the media hollowed out of the cats so it’s running like shit and throwing O2 codes. Smells like it’s running super rich which I assume is because the computer is telling it to because of the sensors not communicating properly but I honestly don’t know for sure. What’s the best brand to go with? Magnaflow looks like the most expensive but is it worth the extra coin?