My understanding was there is a pressue regulating valve in the PAS system to cap system pressure, given the requirement for low speed manoeuvring / parking etc I would guess it reaches max pressure at fairly low engine speeds so any perception of steering feel changing at high rpm on track is likely to be placebo?
I run them on my car (not sure which make), mainly just to give the various pumps an easier time when it is constantly at high RPM - for potential reliability alone I like them.
No idea on performance improvements but if the data (not telemetry unless you are braodcasting it :P) shows an improvement then fair enough - one thing I can say is I don't believe there is any way it can make it slower so why not
