I just bought my cobra a few weeks ago and noticed when I'm driving and hit the slightest bump i can hear a rattle from underneath. I checked underneath and the exhaust was nice and tight. I called the guy and asked him when he lowered it if he took the isolaters out of it. He said he took one off each side i don't remember if it was the top or bottom. Anyways is that what could be making that noise? It sounds like metal on metal.