So I just bought a 2010 CTS 3.6 Performance after owning an STi for the last six years and was underneath scoping out an exhaust upgrade. Two questions, 1) is there an aftermarket exhaust that is an "exact fit", and 2) on the right exhaust pipe hanger, just before the muffler, there is a round plastic cylinder, black in colour and maybe 2 inches in diameter and 4 inches long, that is obviously supposed to be there. But, there is no electrical connection to it that I see. What might its purpose be?