I recently overhauled my '94 with 115,000m and, previously replaced 2 sets of shocks, etc on my '93; which is now around 200,000m. With an '89 you need to carefully look at the rear control arm bushings, as generally you can bypass replacing these on later years.
I would say there are 'must change" items like - on the rear if you change springs you need new cushions (MN 12 now has urethane ones versus the stock rubber) and replace the sway bar bushings (both the bar & the links). For the front you'll need to replace the outer tie-rod ends, strut-rod bushings, lower control arm bushings & ball joints (although bushing kits are available I think it's easier to just replace the whole lower arm) and replace the upper control arms (one piece with the ball joint).
Additional items based upon wear would be the front sway bar bushings and as mentioned the rear control arm bushings. Most auto parts stores will carry Moog or similar branded parts & bushings. You may have trouble getting the front lower arms though, as aftermarket ones are only now getting to market. If you go to Ford use one of the sccoa/tccoa discount dealers, otherwise you'll pay $150 + per arm. I paid $89 with discount. Upper arms are common about $60ea. I tried a LCA bushing kit on my '93 and didn't like the bushing fit and having to press out the old ball joints, which is why I replaced the whole arm on my '94. With Tokico shocks, Eibach springs, both control arms, rear sway bar & the various bushings I spent about $1,000 on the total re-build. And don't forget to have a 4 wheel alignment job afterwards.