Advantages of aftermarket upper:lower control arms

PST non-adjustable. Put them into a 64 dart and they went right in to the stock location. Haven’t swapped the spindle yet (just arrived).
I had to modify my 1965 Valiant to use PST upper control arms (I'm pretty sure those are what I used. Straight tube-design?) Someone provided an image earlier where you have to cut the mount. (Not sure if the instructions said to add reenforcements to replace the metal you are removing, but I did that too... seems like a bad place to weaken the original design.)