silencer ring
IF you like high pitched whine/squeal, take it out. some folks have said it gets old on a long trip towing. mine fell out soon after the truck got home. i like the sound of the turbo "whine" so it has stayed out. if you take it out, be sure to clean the intake of the turbo out carefully to remove any aluminum "crumbs". it's hard to get it out without knocking off a few small bits of aluminum. might not do any damage, but then again... .....