This is primarily to Mark, do you hear any weird sound coming from the GranSport exhaust at idle? I started the car yesterday in rotten 10 degree fahrenheit weather and I heard what sounded like a rock tumbling in the exhaust. I should take a video of it, but it doesn't sound like the exhaust pipe is rattling, it sounds internal. Its not incredibly loud, but its noticable. Maybe its some sort of exhaust flapper that is loose. Given the weather, I'll have to wait til spring to take it in.