After riding with RHinehearts on my Ultra, I decided I wanted something mellow at cruising speed with the trike. I found that the loud pipes tired me out at the end of a 4-500 mile day. I tried the stockers but wanted a bit more, so I chose the SE fatshotz. A different look and nice smooth rumble. At cruising speed the wife and I can converse easily. I think the box on the trikes must bounce sound back to us somehow. A plus for me with the Fatshotz is that they are stamped as EPA compliant. No problems with the LEO.