I was reading the other guys stuff and you can't replace the ball joints but you can replace the bushings. So if you have a good ball joint you can have new bushings replaced. As to the preloading all you have to do is put a jack to the control arm and jack it up till just after the car comes off the jackstand (or before) then tighten it up.
One problem is the good bushings are just a little bit bigger in size and you have to bend the crossmember mount point out a little. I use a jig now but never had any problems just bending it with a cresent wrench