Do you have to put inner muffler silencer for the
super drager 2? If you do, does it help lower the
sound level from the outside or inside the car?

 

I own that exhaust and to tell you the truth it doesnt even need a silencer cuz its sound is deep and quiet. To get an idea of what it sounds like go do a search on is300.net there were sound clips posted of the hks dragger and hiper and afew others. it will help you get an idea of what it sound like while in and out of the car and while reving the engine.