I will say they are pretty good, loud exhausts usually aren’t an issue. The only one that tends to get out of line is this guy: http://www.burlingtonfreepress.com/article/20120130/NEWS02/201300302/Fired-Vermont-trooper-faces-second-driving-charge?odyssey=nav|head
A buddy of mine has had a run in with him at a party and another at a bar. He does not give a FUCK if he drives drunk.