You can put lowering springs in B6 too. Bilstein told me you can use OEM springs or lowering springs. These shocks can take both.
I installed the Eibach springs, and they are much better than the OEM springs. You can feel that the suspension works much better with the Eibach springs; I even find it more comfortable than the OEM ones, but I think it lowered a little more than I wanted in the front. At the back, it is very good.
I have a friend with an EG Coupe with B8 and Eibach, and I feel it is more arsh compared to mine. I'm of the opinion that you shouldn't put EG stuff on MB when there are MB parts available because something has to change in that particular part; otherwise, they are both the same references.
Don't use EK springs because the weight ratings are totally different.
The spring plate is indeed a little bit small, but I have been running it for two years without a single problem.
On the subject of brake lines, I have had mine secured by zip ties for almost two years without a single issue.
Now I need to buy a front camber kit because the camber is at -2 degrees. This camber is a tire killer.
I leave a picture of my Aerodeck with Bilstein B6 + Eibach Springs.