Perrin has the PSRS in house. I am not sure if they are ready for mass sales yet. I'm getting one whenever I bother to drop in and collect it. (I'm local to Perrin)
Drop is more with the Perrin kit: .775".
WL: Drop is .675"
Perrin PSRS has a smaller bearing, and drops the control arm lower and farther towards the outside.
I'll take pic's when I install.