The OBX headers come with resonators, which is different from cats, I tried them just see how bad my mileage would drop off. After two weeks I happly put on some cats. I will check my profile to see if I had put pictures of resonators in there, if not I will so you can see for yourself their not cats. Thanks for looking at my truck.

You bought this right? OBX HEADER
And the OBX's cats were giving you bad fuel mileage?

Thanks!