Not installed yet but looks good. I chose this metal core version over the ceramic version as people complained that the ceramic blocks rattled over time. I just hope this gets rid of the excess gas smell coming off my 2015 mustang with long tubes without coils. I'll try to overcome the smog, but I think that's not all. I photographed the inner core as there was no one around to make the sign of the Cross. I'll be happy if it kills the musky exhaust coming from my car. ** Update ** A month has passed since the installation. Nothing rattles and there is no smell from the exhaust. Sonically, this reduced the noise by about 2 dB. Still sounds nice.