I have hydro assist on my rig. 1.75" x 8" ram. This is really a 1.5" piston. Not sure why they "size" a ram on the OD rather than the functional ID of the bore. Whatever. It works pretty good, couple things to note.
1. In response to
@skippy, if the PSC box is too light feeling, see if you can order it with a larger diameter torsion bar controlling the spool valve. Don't know what options they have available, but a quick(?) phone call should answer that. Bigger bar will = crisper, "sportier" feeling steering. The power assist won't change but your perceived effort at the steering wheel will be higher to fully open the spool valve with the stiffer torsion bar.
2. Along the lines of
@xjtony, sizing the pump is pretty critical and if the pump is undersized (or ram too big), steering will be heavy while you wait for the hydraulics to catch up. If you are set on hydro assist, I'd second
@skippy's recommendation. Skip the PSC box and just port a factory size box (or buy a ported factory size box from PSC or somewhere). The hydraulic ram will provide most all of your steering force and the smaller stock size box will have a smaller volume requirement (thus preventing the heavy steering when trying to turn quickly). If you just want more power and are going to avoid the hydro assist, why not go for the bigger diameter box, it will increase your steering force. Although it likely won't be enough to make it easy to turn on slick rock with lockers engaged for example. Probably won't be much different than your steering now when things start to bind because of traction.
3. Also along the lines of
@xjtony, make sure your ram, box and steering stops are all timed so everything bottoms out at the same time, otherwise when you get to the extremes of your steering, the ram can cause damage to the box if it has more travel and the box is at its stops. Not a very fun day to twist a sector shaft off. Or like Tony's experience let the ram tear the knuckles/ball joints apart.
My $.02.
