That is my understanding. The LCA handles braking loads and positions the spindle... the UCA works with it to handle the alignment.
With the bushing type rod installed and T bars out and everything greased there is some resistance to up and down movement. The strut rod + bushing effectively has some very slight spring rate. I guess the Heim joint type would not. Also the "pivot point" on the bushing type would be in the middle of the bushing pack while the Heim joint pivot is behind the bushings. The Heim is effectively shorter and the LCA would have a shorter arc. Its not clear to me what the benefit of the Heim type is.
I use a Teflon lined joint that usually lasts many years of the typical part time usage our cars see. For me, combined with my delrin lower control arm bushing I am looking for the most precise movement possible. True, the arc is changed from the stock arc, but its not something one would notice.
