I removed the back seat on my '13 JK and found exhaust noise increased quite a bit. I believe the back seats/head rests must have been absorbing the exhaust noise before, but it increased when they were out. The only thing separating the cab of the vehicle now between exhaust pipe is a piece of glass and a tail-gate with no insulation. I took it into to dealership to get a free oil-change and I brought up the exhaust-thing and they said all connections were fine. I actually like it, my wife not-so-much. It now has a raspy sound above 2500 rpm and a little burble at idle. Anyone notice the same? Hard-top is still on and may reverberate the sound.