Installed on my 2007 Infiniti G35 6MT coupe. They sound GREAT and add a little more power. The quality of the work is excellent, no complaints! I highly recommend either adding them to your already modified full exhaust system or doing the entire exhaust at once. If you install them on a standard system, it will sound a bit hoarse and you won't see any performance gain. My exhaust = DC Sports header, Fast Intentions high flow resonant cats, Megan Y-pipe and Megan muffler.