what he said.
these go one step beyond the camburg and total chaos offerings by protecting the uniball from debris, and minimizing rotating resistance around the mounting bolt by using heims.
the old style, the sort that used the stock upper ball joint, didnt really do anything other than they were lower profile so a wider section could be run without spacing out the tires. it was rare if they really did correct caster for lifted vehicles, but that was often a selling point--the target was owners with lifts, not owners who needed travel.
single-shear uniball designs allow more droop than the stock upper ball joint, and provide a much stronger joint. unfortunately, if the uniball is left as the droop limiter, it passes the stress to the spindle, which will eventually break from fatigue loading. swayaway/camburg and donahoe both provide coilover kits which use the additional downtravel--about four inches--available with the uniball joint but limit travel at the coilover before the joint hangs.
4" might not sound like much, but when stock is only 6", it's a world of difference going to 10. of course, there is no benefit to the uniball upper control arm if the vehicle is not equipped with suspension capable of using the additional travel.
theyre expensive because theyre a small run of custom machined parts--the arm and the cover. for the money, if you have the shocks to use the uniball, the camburgs are a much better deal as long as they have a grease fitting. if not, it's easy to add one. btw "shock to use the uniballs" means pushing an 8" shaft and running strap-limited. it takes longer to set up but has a lot of benefit, including to people in the expedition community.
-sean
