I have one on my M35 and to date have never been hassled by cops. As Scott said, great for going thru RBT's, cruising down the road when police are present, and on long trips. It's nice to have the control to turn the volume down when you need too I also had one on my R34 without any hassles and worked a treat!! Both have been the 3" oval ones with the single 3" inlet & the dual 3" outlets (VMK5-300), so looks stock. I've also got the remote velcro'd to the inside of the glove pocket on top of the dash (where the pop-up TV is on other models). I must admit, it has a nice rumble at idle when fully open and quieter than stock when fully closed and like others, has saved me plenty of times from *unwanted* attention. When it's open, It does get quite 'droney' at times in the cabin, but mates have said that it's not THAT loud from the outside either. I worry more about the flutter I'm getting from the turbosmart BOV!!