What ever really, years ago I would have said Moog or nothing, but the last couple sets I have installed went to junk way to quick. It has been a long time since I have done D30 ball joints, but I believe in order to do the top, you need to press out the bottom, so since you need to press them out, might as well replace both upper and lower. I would check to verify that, it might be the other way around, inorder to do the bottom, you need to remove the tops.