Okay, I know the fundamental difference between the two is the 16432 has metal substrate cats and the 15448 probably has the "high flow" ceramic. What I want to know is do they both cause a CEL? I read before that the 15448 does not, I'm hoping that the 16432 also does not? Not that it really matters since I'll be taking it to the dyno a few days after installing, but I was just curious. I will be running JBA shorties, Magnaflow X, into a Magnaflow 3" Magnapack catback, so stoked. Feedback appreciated. Thanks! Matt