How do you replace the trunk struts on a 1998 Mercury Mystique?

(Licenced Technician) -- 1990 Mercury Grand Marquis does not use struts. It uses coil springs with separate shocks for the front and rear - except for some of the upscale trim Grand Marquis models, which run computer-controlled air suspension in the rear. Why are you wanting the "struts" changed? Are you having handling problems? Does the car sit low on one side? I have owned a 1991 Crown Vic and a 1989 Grand Marquis; front shocks are not really difficult (for me) to change; front coil springs are much more difficult. These cars were known for sometimes breaking coil springs. Unless you have a good solid garage floor, a couple of floor jacks, a complete set of line-up bars, and access to air tools, I would not recommend doing this job yourself. Hope this helps.