I have been getting concerned lately with all the laws coming down so last year I purchased a set of DB Killers. I had a dyno-mapping session scheduled and had brought them with me and ran with and without. As expected they knocked a few hp off the top but what I didn't like was that they created a dip in the torque in the 4500-6000 range, right where I spend most of my time. So, I have not used them on the street. I personally enjoy the sound of my bike but I notice that a lot of people look over their shoulder when I am approaching. I try to gauge their reaction and so far they don't seem to give a negative reaction, more curious and or interested. I guess not all sounds create the same reaction by volume alone.