Neighbor Hater Mufflers for FL - ChromeCobra's Neighbor Hater mufflers are not for the faint of heart. These are an aggressive slip on muffler, for those who think loud just isn't good enough. Start as round 4" tubes, then bell out to 4. 5", for an aggressive and classic design at the rear. Internally, these mufflers have a perforated core with strategically spaced holes; This is done in order to produce an aggressive bark. At the end of the baffle is a trumpet shaped inner tip that works