Sorry for the slow reply.
As far as these being genuine Koni creations, I can say that about a year ago, Greg started digging through all our suspension parts to find proper strut housings and so forth to ship off to them for the engineers. A year and lots of work later, these are the result, and they were 100% designed and created by Koni to their Sport Yellow spec of struts. Here is the official Koni release: http://www.koni-na.com/en-US/NorthAmerica/News/News-Releases/KONI-Sport-Performance-Dampers-for-Classic-’70-83/.
Don't be surprised if Lee from Koni himself jumps in here at some point. Koni has been absolutely awesome through this process, I think we're all lucky to have Koni wanting to invest in Classic Z's.
As far as the bump stops, by "proper" they basically meant having properly designed and undamaged units, trimmed if needed based on spring height. These units do not come with bump stops. The factory rubber ones are acceptable, and our urethane ones might be the best bet for progressive "bottoming", in addition to the fact that they fit the shaft sleeve diameter perfectly. As far as the Koni "Silastic" Foam Rubber (i.e. Silicone) bump stops, they look like a great progressive option as well. They are not model specific, and may not fit as snugly as our urethane ones (we're going to get some and try, and let you know), but we're looking into offering those as well. Assuming the Amazon seller has the right part pictured, you can see one of those ($26.56 each? Ouch!) here: https://www.amazon.com/Koni-70-34-54-000-0-Bump-Stop/dp/B001G99RKS.
As far as the hardware shown above, the top left is the shaft sleeve. The sleeve fit is perfect. I'll try to find a spring seat if possible and show some of it fit together.
Below that in the image of course is the top locking nut.
On the bottom left of the image is the I-realize-now-I-should-have-exposed-that-in-the-image-better Gland Nut. I'm looking for inexpensive options for tools so you don't have to use a pipe wrench. Will advise.
On the top right of the hardware shown is of course the adjuster knob. Since you get one with each strut, you can loose three of them and still be ok... ?
On the bottom right is their "washer" to go on top of the Gland Nut. It is designed with channels and waves, the purpose being an added layer of protection for the seal underneath, as it will direct away any air pressure when bottoming, or road junk that bounces up there, so it doesn't end up crammed on top of the seal.
We'll work on a digital version of their instruction sheet, but they are a bit generic and have nothing special I can see beyond standard info. Other than the placement of the disc and the Z-specific sleeve (which aren't shown on there anyway), there isn't anything that would surprise anyone who has gone through cartridge install before. They do however have a diagram showing you how to place the adjuster knob in your glovebox... ?
I'll check with Hector on Illumina's. It won't surprise me if he has experience with them and can offer some comparisons. Stay tuned.
You may have seen it on our website already, but here is a quick illustration of the adjustment: https://youtu.be/HM83qhwRB30
James will be following up if we missed anything. Thanks for the interest!