I've been debating it, and reached the following conclsions having driven the following setups:
S4 TII power steering (speed sensitive)
S5 N/A power steering (don't know what it was sensitive too, was my first RX)
Depowered power S5 TII
True manual rack S4 N/A with 225 series tires.
If you want manual, go to a TRUE manual rack. The depowered unit has just a little too much effort for my liking, and the unit in question was a *true* depowered version, had the little "piston" removed from the center, the whole ball of wax.
I found a manual rack on here and it'll be going into my FC over the winter....along with too much other shit that I don't have time for