My intrepid has a center resonator that is 2-1 then a muffler and a second resonator at the rear. A long time ago I chopped the rear resonator and muffler off and the car sounded real good at idle but had a horrible drone. I installed a "glass pack" and no more deafening droning noise and is actually quite tame. I suggest about 18-24 inches of pipe after any sound altering device you use.
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