Traditionally spherical ends are used to more positively locate a suspension member. Ours do the same for the rear end. We suggest using old bushings in the upper arms if still using them.
Our units are 100% bolt on. Make sure if looking at other brand arms that you do not need to drill out the chassis or rear end. See most supply 3/4 rod ends since metric rod ends are expensive and hard to get. We fixed that with a trick that has been used in motorsports for a decade. Ours use the stock mounting bolts.
-billy
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