I just went through this install towards the later part of the crusing season, so I don't have a couple of thousand of KMs to remark about, but for what it's worth....

So to baseline my feeback, I started with the following combination:

1) 1980 M-body Coupe, using a pretty tight factory box (literally no float in the middle)
2) previously installed the pressure-drop shim kit in my power steering pump, so the ride was already pretty tight feeling, but yes, that good ol' Mopar squirly feeling was still there
3) my Coupe is set up with handling as the focus, so fleet car large sway bars, KONI adjustable shocks, all new suspension pieces with about 6K miles since a total rubuild

Alright, so following the install I will say this:

1) there is noticable improvement in ride stability, no doubt about it
2) was it a 'Day & Night' type of a thing...??? Nope, not for me, but I attribute that to the decent handling baseline I started off with
3) what AndyF remarked on was very true for me as well, and a real PITA at that...trying to find the right fittings to bolt it all together...my oh my, it felt I was literally hacking this thing together at times
- here is a Moparts thread of mine on this very topic
- I am running a power steering cooler, so perhaps that complicated things a tad more
- the power steering pump high-pressure hose used by the factory uses a weird (to me LOL) fitting, it's not a straight forward flare, rather it's an O-ring type retaining flare (for a decent pic and description of this check out the above thread I linked above)
4) I did actually run into an issue with the 1st unit they shipped, cross threaded bolts on the head piece (2 of 4), the exchange unit had a crooked dust seal on the pitman shaft, which I was able to correct, see this thread
5) finally, last but not least, take a look at the attached photo, those are 1-7/8" TTI pipes and while I do have a pretty good amount of room, but it gets HOT HOT HOT...so I am planning on wrapping the power steering hoses with some heat deflecting sleeves

Ohhh...almost forgot: I made up my own direct-fit-coupler. Basically took a factory piece and had a local race shop weld on the fitting with the correct spline count. Yes, you can get these on-line from Bergman, but holy molly the price...I couldn't afford that!