One problem related to front seat head restraint has been reported for the 1998 Mitsubishi Montero. The most recently reported issues are listed below.
At stop light. Hit in rear by car going atleast 45 mph. Neck whip-lash despite 3 point seatbelt and added thickness headrest as seatbelt collapsed backward to horizontal position. Unable to move seat fully upright (80%) after that. Car pushed about 20 ft. Tow hitched attached to frame reduced further back damage. Metal particles found in differential - probably form impact moving car in stopped position.