I just got the w158 inserts installed.before I didn't care for the sound of the bike it has 3 1/2 slash cut slip ons that I think are rush mufflers.the pipe on the right side seemed to have a ping to it like something was loose in it.i removed the baffles and put the inserts in,I am totally impressed this thing it sounds awesome now.i have them with the bolt facing the outlet of the slip ons,when I had them turned towards the head pipe I could still hear the pinging a little so I turned them and it is gone.glad I didn't spend the money on new slip ons.

 

I'm a fan of the torque inserts. Not only did it deepen the tone a bit, it also flattened the dead spot I had at about 2000 rpm after I did the Stage 1 Harley Tax. I believe I have the bolt facing the front of the bike.

 

I downloaded a decibel meter app for my iPhone.fired it up with the phone on the floor about 10 ft behind the bike and got 90 decibels,wound it up to 2500 rpm and got 101 decibels.again this was done in my garage not outside.

 

You'll get a higher reading inside the enclosed garage (even if the garage door is open) than you would if you did the measurements outdoors.