Tires are the only thing which matters. All the suspension and aero do is give parameters to the tire load and slip simulation.
They should be reasonable, but I'll take another look. Ignore the KS CTR tires, they're just hacked together. I had them initially on my CTR and it just wouldn't turn.
You are right.
I just realized I made the swap with a version of the CTR tires I modified some years ago...
Problem is it was on tire model 7 and by importing the same parameters in tire model 10 it drives very differently (in a bad, bad way).
Maybe I did something wrong, I'll check tomorrow night if I manage to find some time.