I can only guess that R is referring to Moog's lower end parts as in "RK" opposed to "CK" higher end parts. I would not get any brand of low end parts for ball joints.
If you feel that your control arm bushings are okay still, then you can get the smaller passenger side upper arm factory replacement to replace the ball joint. For example:
More Information for MOOG CK8710T
This is easier and if you note the position of the caster adjustment bolt on the current one, you can get caster close enough putting the bolt back in the same position with the new part and not need a front end alignment done like you would if using the one piece control arm linked below, yet you will still need an alignment done after replacing the driver's side upper arm. Some people opt to put on a new alignment bolt kit, as would I when replacing the entire control arm on either side, or taking it off to reuse with new bushings:
Suspension Parts and More for Your 1998 FORD EXPLORER at Reliably Low Prices. Fast Online Catalog. DIY-Easy. Your Choice of Quality. Full Manufacturer Warranty.
www.rockauto.com
If you do want to replace the upper bushings then you also have to either buy individual bushings and press them in,
or switch to the one piece upper arm that already has new bushings installed then you don't need either of the above.
Sway bar end links, I got Moog last time and would not get them again because they downgraded them to hollow (!) hard thermoplastic bushings where they were formerly translucent white polyurethane. These are the downgraded Moogs, they finally updated the picture to reflect the bushing change:
What I'd do now is get a standard kit (normal bolt, sleeve, and nut, not that funky end collar design which needs higher inner diameter bushings, and replace the bushings with some Energy Suspension polyurethane. The standard size, ES part is 9.8105, or you could cut down ES 9.8103 for an even better result. You can find a post in this forum by member Swshawaii on how that is done, OR you could just run the bushings that come with the kit you choose and when they fail, replace just the bushings if the bolt isn't too rusted to reuse. Threadlock compound is good to use on the nut end to slow down rust, not required but every time I replaced my end links I ended up having them shear off (or used an angle grinder to save time, lol) upon attempting their removal.
