For the two times i have done it, I only separated the uppers and everything worked out fine, the second one I almost didn't at all, i almost had that thing removed without the upper or lower ball joints separated...but that cv was also grenaded <img src="/forums/images/graemlins/lol.gif" alt="" />, so it had a lot of play to work with <img src="/forums/images/graemlins/smile.gif" alt="" />.

edit:
don't know anything about removing them withough separating the ball joint....i guess it would work...maybe? can't remember how much room there was, it was just much easier/more space to work with when the upper was off