I would recommend the boxed control arms and the sway bar I have a set in each of my 65s, it really improves the handling . The weld in kit is great just make sure you get the arms blasted or clean them real good to get a good clean surface to weld on to. Now I purchase new rear arms from OPGI about $ 200 for the set. It's worth it for me because before I had to weld in the plates, buy the bushings then find a shop that was willing to press them out and in, plus my time running around.
When you put the sway bar in you will need shims. I have a set that I don't need, you can have them. just let me know and I will send them out to you.
Tony