If it's repeatable, have a friend stand near the noise origination area with the hood up (head in engine bay, ear triad downward), turn off the car, presumably without the clutch pedal down, in neutral. Check for where it emanates from. Look for shrouds that cover the exhaust pipe (heat shields) that may be a bit loose and rattle a bit against some other metal. Have your friend watch the general engine movement and vibration (with clutch in and out to see if there's a difference). Without a load, engine shouldn't vibrate as much. Also see if the engine moves "sideways" or "front-to-back" when shutting off. Will help further determine what part might be rubbing. Also have your friend put his/her head underneath (near front tire) if it seems to be coming from underneath rather than on-top... Good luck... PS - record the sound and take it to Chrysler techs if you have a PDA or some other recording device.