Hi Steven,
Josh just gave me your email so that I could respond. My name is Sam, I'm the guy that designed the exhaust. The exhaust was designed to improve torque, and we achieve this, by modifying the muffler. The G6 just like the Malibu is a fairly heavy car, 3500 plus lbs. Torque is not something you can afford to lose. Many G6 owners have found this out the hard way by going with the typical big pipe system that others produce. Our system uses 2.5" mandrel bent stainless which insures optimum flow, the muffler we modify acts as the regulator. This is what allows the engine to produce more torque down low, and more hp higher in the rpms. I also designed the system not to sound like other V6's or in any way like the typical fart ricer sound that is associated with many aftermarket exhaust systems. We went after a European sports car type sound.
Hope this helps,
Regards,
-SAM-
Classic Performance