I would be careful about turning curb, road and slip FFB down to 0 on FFB settings for any wheel. I realized this after playing with the DS4 controller settings. Turning steering speed to 0 or filtering to 100 turns steering off completely!
With this in mind, I thought about how I recently turned curb, road and slip down to 0 after some people here commented "eh those are artificial." With those at zero, my FFB was crazy dead. At 1, it came back alive. Especially noticeable was the carousel at Nords... nothing through the wheel around there with those at 0 and that's just wrong. Now I believe those settings are an amplification factor of non-artificial effects, and that the default settings are Kunos's best estimate of the average "real" feeling.
The exception of course is understeer effects, which seem to be artificial and certainly feel so with T300.
I could probably look around on here or AC forum to confirm or debunk my suspicions, but this whole thought/typing process took 9 minutes which is a lot less time wasted for me.