Saw you said people could post feedback here in the support tab.
Only really driven the DTM so far, and the rear end has slipped out while maneuvering across the track for a corner with minimal steering input in as high as 4th gear a couple of times. This is with the stock setup you've provided. I don't know if this is just the Nordschleife being uneven and me getting unlucky, but the KS variant hasn't done anything like that to me yet.
Other than that, I don't know if it's just because I'm so used to vanilla car, but yours feels kind of... Muted? I'm fairly casual, so I'm not really that proficient with setting up the car yet. I tried fiddling a bit, but I couldn't get it as direct and acute as the vanilla.
I'll play around a bit more and come back to you if I have any more feedback.
DTM springs and ARBs probably aren't the best for Nordschleife. I'm not sure if they ever even ran these cars on the old course. The bump compliance will get worse at high speed, not the other way around due to how the damping is setup, namely too stiff due to rule limitations needing a compromise.
There's some stories of Japanese mospo teams in other series coming to run on Norsdchleife, with the usual setups they run (Similar to the DTM car, very stiff with no compliance because of Japan's smooth tracks) and them just getting destroyed.
I don't know if it's entirely realistic, but everything lines up very well, and all video I saw of E30s and 190's in Gr. A and DTM spec even lightly driving over kerbs resulted in numerous and quite violent vibrations on the whole car. The lack of downforce makes it especially bad at high speed. Kunos modifies some of their cars sometimes to make them easier to drive artificially, like more rear grip (ESPECIALLY in the Yellowbird!) while I avoid it completely if at all possible, so of course the bad things of the real car will appear as well, not just the good.
Kunos tires have incorrect relaxation length and load/camber curves, so they probably will feel a bit too snappy near center indeed. So more proper cars can feel a bit "muted" as they take a tad longer to respond: which is desirable.
My cars are all easier to drive than the KS variant, but that's just because the original real cars are so good, not because mine are "too easy" per-se. I still think all sim cars are a bit too hard due to how tires respond when going over the limit. And roadcars generally have some toe-in flex from bushings stabilizing them even more, something we can't really do in AC.
I also lean towards a bit softer FFB based on what I've heard from drivers of the R34, FD and E30 at least.
Give the more stock cars a try. I'm pretty proud of the base model Sport Evo.