Got 96,000 miles on my '99 Mystique LS, 2.5, ATX. Besides regular maintainence, only thing was a new set of Michelin Rainforce tires at 40,000 miles and a serpentine belt at 96,000 miles. I commute 100 miles daily to work, all Interstate driving.
-Mark- '99 Mystique LS all options, pure stock 93,000 troublefree miles (knock on wood!)