I have a set of those too, and they are great except for a popping sound they make which is probably due to my specific rate springs being to stiff…
That popping noise is due to the center mount being too tight. The nylon/urethane rubs the mounting bracket. I used 1mm shims, on either side, so the bracket would clamp to the steel bushing and not squeeze the urethane. Shims are needed on the outers, as well, to maintain mounting geometry. Arm should have not side to side load. Should swing up into the center bracket without having to push towards the front or back.
Lot’s of grease, install, and popping gone.
Link to shims
I built my own set from materials purchased from SpeedWay. But had to have new steel bushings made for 12mm ID. The ends only come in SAE. Doesn’t take much slop to make them rattle. Would be wise to ask seller what side ID the bushings are.
I tried T3RapTops heim joint links. They wear quickly and rattle. That’s why I went with the solid style listed here. And used shims to eliminate the popping/squeaking.