Nvidia drivers 440.66.07 (beta) seems to have boosted performance in Wreckfest by maybe double. It’s still half of what I get in Windows (80-100fps vs 33-50 in linux) with:

24 cars on screen

Ultra settings

Fairfield demolition

I also have an issue where if I don’t have g-sync enabled, then the steam overlay FPS counter seems to show a cap of half my max refresh rate (50 for 100hz screen), and it never seems to dip below 33fps. G-sync enabled appears to allow higher fps, and also never dips below 33fps. Because of this I’m quite uncertain of the actual impact or fps accuracy, but the game is feeling very smooth.

TL;DR: It seems the D:E fix also had a big impact on Wreckfest