Sounds very good.. Gas Mileage from Orlando to Miami with the wind behind me was 20Mpg the entire way there @ just over 5-10mph of the speed limit and on cruise control. On the way home, I fueled up, drove into the wind the entire road trip home, 5-10mph over the speed limit was was worried that the vehicle would have to get used to the exhaust air flow.. I actually averaged 26.1 the entire trip home, and was very pleased with it. Sounds a bit louder than the 350z and Infiniti G35-37... All in all, a very nice rumble but not raspy. I wasn't a big fan of the exhaust and have actually knocked it on this forum a few times but I wanted to help the OP out because he was looking for an OEM system and this was FREE.. Had I of had the option to pay for it, I wouldn't have spent a dime on it.
Orlando to Miami [location of install] was 259 miles.. Took me 5hrs with traffic on the way there and just at 4.5 on the way back.. My Edge has 22's on it and I was very pleased.. Cost me 100$ in gas round trip!