I know somebody that put a WJ steering pump in their '00.
I don't know why. He runs regular tires like me, mine is just a DD, but said the steering was hard too.
Bottom line it was nothing but problems and went back to an XJ one.
Could be user error. Who knows.
The Saginaw box Jeep uses is considered the "better" box over at G-bodyForum.com. It only came on the F-41 equipped G-body cars like Monte Carlo SS, Grand National, 442, etc. But you could get it as an option on lesser models. read: https://www.motortrend.com/how-to/upgrade-g-body-steering-cheap/ Here is a chart with some specs.