Looking for a little advice here. I currently own a 2001 Jeep Grand Cherokee Limited 4.7 liter. I am thinking about putting on a K&N Air Intake System. I have been told that if I do something like this I should in turn upgrade the stock muffler to accept the new level of air be tooken in. Is this true? What are the downsides to installing a Air Intake System? Is K&N the preffered brand over Airraid or Volant? If anyone has done this to there jeep (same model) please let me know what your experience has been.