[video]- YouTube
When i was testing my vehicles i always worked at 100-120FPS. But i forgot that most people would play this at around 60fps. So I think just slowing the Global Time Dilation should work! 
You will likely want to check out this blog post.
I did try but it doesn’t change much. I just locked frame rate at 60 and set the Global Time Dilation to 0.5 and it works the same way as if it was set at 120 fps and the Global Time Dilation to 1.
Actually physics sub-stepping will help in this case you just need to set a proper maximum time step. By default it’s set for 60 updates per second, for 120 it should be set to 1/120. This will help if someone is running it at less than 60 fps as well.