Just a bunch of personal changes that I think helps boost FPS, loading speed should be faster too.
Replace the file in ...MT - The Dream\Client\S1Game\Config
, you don't have to set it to read-only.
In-game settings guide: https://docs.google.com/document/d/14XwofIk2sYu7Ga_p8Kyq-0igzTnuFU-B_aqno2lfu7E/
References: [1], [2], [3], [4], [5], Killing Floor 2 Engine/System Settings