My 2 cents on the subject - I replaced both steering stabilizer and rag joint on my GW.
Old rag joint was cracked/torn and I wanted to keep steering feel. I used
rebuild kit from BJs, they also sell complete coupler (
for 1974-76 and
for 1977-91) if you don't want to mess with old one. IMO, buying complete coupler is not worth it unless your is broken, it is 3 times more expensive ($75 vs $23 for rebuild kit) and it's not difficult to rebuild. Rebuild kit might also be available at your local parts store, if you don't want to order online
My old steering stabilizer had couple dents, leaking and bushings were almost gone. Used
BDS NX2 (also from BJs), it's probably a bit of an overkill for my stock rig, but whatever. No hardware is included, so you'll need to reuse stock stuff. It definitely improved steering - driving on washboard dirt roads became less scary. Keep in mind that not all Jeeps had that stabilizer and a lot of people drive fine without it for years - it's not
crucial part of steering, but IMO having it makes steering nicer.
And x2 on what Stuka said - it's better to figure out source of vibration first (especially if it's not the stabilizer) and fix it. I can imagine that extra vibrations would shorten the life of new stabilizer and it's bushings.