After a few weeks, and after getting over the initial disappointment with the springs lowering the car more than advertised, I'd like to offer a review.
My goal for this car is replicating the spirit of the CSS with my 2019 Rabbit GTI, thus why I wanted less than an inch drop and nothing too harsh.
I installed these springs on my new factory struts with Eurosport's camber kit and a 26mm rear sway bar.
I was driving on my RE71R's right after install and the ride was firmer than I wanted on the street. Not bad, but definitely a little harsher than stock. Once I installed my street tires, they were exactly what I wanted on the street. TIre and tire pressure will be critical to getting good street manners.
I did have one concern though. Even after a week of intentional hard driving, the right rear was sitting high, even after removing and reinstalling the spring. Swapped left and right rear, now left was 1/2 higher. This was causing uneven ride height at the front too. I sourced a set of R springs in case they didn't eventually settle, but decided to get it aligned and shake it down at an autocross.
First, the car had much less body roll than stock. A lot less. Back on RE71R's, the car felt great at speed, soaking up the terrible asphalt imperfections on the old cracked and pitted runway. Again, transitions were well controlled, no brake dive, though strangely, the car was harder to launch without getting wheel hop on the broken asphalt, but easier on smooth city streets.
Second, these springs, 26mm rear sway, -2.3 camber front, -1.8 rear with .02 toe out front, .02 toe in rear, 32 psi on 245/40 17 RE71R's, handled amazingly. Sharp turn in, allowed perfect trail braking (I've also turned ESC completely off and all the abs nannies too) put down power, and felt really composed. I came away loving this car even more. In stock form, even with a RSB, it's a bit tedious to drive these cars fast. With the above setup, it was some much fun to throw the car around and get it to dance. Easily the best of all my previous GTI's and feels are fun to drive as my old Corrado VR6 did.
Third, the springs don't feel under dampened with good factory shocks, though if yours are worn, I'd just suck it up and do B8's. I've used Koni sports on many cars over the years, the last one being a 15 Miata Club, and I just don't think they'll pair as well with these as the B8's.
Fourth, after 3 drivers doing 7 autocross runs each on 200tw tires, the springs have settled. Fronts are both equal, rears are equal.
So, if you can get passed the height thing, which I have, there's a lot of value here if you're building a mild streetable STH, a canyon carver and/or mild track day car. If it's just for street, they are on the verge of being to stiff, but a little softer sideway choice really is about perfect and is wife approved by my wife that is very sensitive to ride quality and drives a Mercedes SUV. I went with FK510's, but ESC, MPS4S or MPSS would work well too.
Overall I'm really, really impressed, even after my initial anger over the ride height. I would give them 8/10, which would be a 9 if the drop were .25 less. I'll update with news of how my stock struts hold up, which I should be a good case study, since I drive 90 miles a day on the street and track and autocross the car once or twice a month.