i know a lot of you are waiting for the cats or at least my review of them. Please be patient. testing takes time. but what i can tell you is that these things are awesome.just like there exhaust.there was a significant gain in hp and trq. and it has been dynode twice and will post graph when testing is complete.the sound is much greater than that of just having the exhaust. and my gas milage has increased slightly. so please all i ask is that you be patient.they want to please all the people who buy this system and not just some of the people. again thanks for everyone interest .