Thanks for taking the time to reply in a detailed fashion and trying to replicate it. And apologies for over-heating.
As I said, I tried a lot of settings and don't see any difference. For compression, I have been using MaxHUD with a threshold of 1% to see "bottoming out" as well as replay verification. Easy enough to do when playing as the icon stays for a bit. For this, all my tests indicated bottoming out at the exact same spot when taking the same line at the same speed. General behaviour was also unchanged (hence why I moved on to modifying the cfg and carried on the same tests with the same results).
For rebound, I chose a jump face that I knew I was bottoming out on, and took it at same angle, same speed, same position several times with different extreme rebound settigns. Then I counted how many frames it took for the rear to go back to full extension in replay mode, Orbit camera. No changes were seen (I think 5 frames?). Similar story with cfg changes.
This is why my conclusion was an issue with suspensions values being called.
I doubt it is a perception thing because as I said, some really stupid values where put in the cfg (I changed every possible suspension value multiple times as you suggested).
Now if you don't see the same behaviour, while at least some other players do see it, it might be a problem on "our computers". Meaning, the install file didn't work as supposed (mind you I have a 100% clean beta8 install), or the settings are not properly saved / called (which might be a reason for the online garage crash that you can't reproduce). I know Windows 10 has issues with games since the last Creator's update, but I'm not reverting my OS for that :p I will run some more tests with administrator, compatibility, check some read-only parameters etc.