Sorry Matt!
Background:
At the same time I installed these I also installed Powerflex sway-bar bushings and Li Customs adjustable sway-bar end-links. These spherical bearings were installed in NEW Lemforder thrust arms. Ultimately, I decided to install them in new arms simply for ease of re-installation and so I would not be bothered in saving the ball joint/boot or having to press out the OEM bushing.
My car has 98k miles on it, GC coilovers (430/340#) and is running square OEM wheels with PSSs. It turns out that I needed a new thrust arm or, at a minimum, a bushing on the right side as the old bushing was worn to the point that the tire was rubbing slightly when at full right lock. Both bushings appeared fine once they were removed from the car and there was never any noticeable affects under heavy braking.
Fit/Fitment:
They of course fit with zero rework required on my end. They were installed in about 45 minutes and I had everything buttoned up on the front end in about an hour.
Appearance/Quality:
Top notch and they are really beautiful in person. I am
PROUD to have these on my car and to deal with Matt is truly a pleasure. I will not hesitate in purchasing the matching REAR set when they are ready.

(hint, hint!)
Review:
After approximately 400 miles of various driving scenarios over wide ranging surfaces such as uneven pavement, rumble strips, expansion joints, potholes, broken cement/pavement, metal grate bridge decking, smooth high speed surfaces, rural roads, grooved freeways/highways, I can honestly say that the ride is unremarkable. What I mean by unremarkable is that in general driving, I do not think that you could tell the difference unless you were really trying.
That is to say, the
basic ride quality/demeanor is not affected and I do not notice any additional "jarring" or "shock" events from surface imperfections or design elements than I did before the install. I truly believe that this is due to, in part at least, the superior ride quality afforded by the Koni/Eibach setup I am using. I do notice some "noise" on various road surfaces but it is not detrimental to the overall experience nor does it annoy me and it is REALLY hard to say that it is any more present than before. I had to really take a day of driving and actually "look" for these differences, as they are not glaringly apparent at all, in the slightest.
The big difference, one that I was not expecting so, is how much sharper turn-in and steering feel is after the install. There must be more play in the OEM bushings than I expected but the car instantly responds to minor steering inputs but not in an intrusive, excessive or dangerous way.
Overall:
So, obviously they are better than that(those) apparently worn bushing(s) but the entire car feels better than my last M5 did and that M5 had had a COMPLETE (I mean COMPLETE) suspension refresh about 8k miles before I got it.
I truly was expecting a drastic change in ride quality (for the worse) based on some of the reviews that I had read concerning monoball installations even on cars other than the E39. The change is hardly drastic as far as ride quality is concerned. It really only makes the car better, not different.
The benefits of these monoballs that I see looking forward:
1) The thrust arms become infinitely serviceable limited only by the life of the ball joint.
2) The bearings themselves are replaceable, serviceable in your garage or driveway, cheaper than purchasing an entire thrust arm(s) and require less maintenance to replace than R/Ring the thrust arm(s) in whole.
3) The car will feel the way it feels now for a lot longer than with the OEM thrust arm and will not suffer at the hands of a failing thrust arm bushing again.
I LOVE them. They definitely improved the response and feel of the car and I highly recommend them.