Just like Micheal was saying you can get a system that is invisible on the road and amazing offroad, but you have to put up the cash. I have a PSC kit on my TJ w/ 40" Treps + D60 + Detroit + Drive Flanges. I get it up to 70 mph on the road around town, city streets, hwy no problem. Offroad no problems using my tire a pivot point either.
But, to answer the original question I have a PSC Durango steering box and pump on one of my other Jeeps and it does great on the street and trail with either set of tires/wheels I run. 36" Iroks on TR beadlocks or 35" BFG MTs on Alloys