I've had a little play around with the scrape and dent settings in the GlobalCarAttributes.xml file, and this is what I was able to find. The original settings are:
I don't know what these numbers referred to whether km/h or mph, so I took the assumption that they would be the former as it's easier to be more accurate. The first change I made was to the scraping, with the following settings:
Which produced the following results. As you can see, it didn't work - the denting remained intact however the scratching didn't occur at any speed, leading us to believe that there must be a valid minimum radius value of 0.15.
You can see with these pictures, specifically towards the top edge and top of the arch of the front wing, there's a marked difference in the impact between 20mph and 50mph, which there should be. However, as mentioned before, the denting didn't happen so we definitely know that there is a minimum of 0.15000 radius for both scrapes and dents.
I'll conduct further tests with the maximum value as well to see if I can reduce the upper range so overall the scrapes are reduced as less excessive.
That's why I just turned the visual damage off. You can play with the speed settings and get the first tier of scratches harder to trigger but overall, the texture is the texture and it seems to be in 3 tiers. I personally would be happy if it just stuck to the first tier of scrapes and dents. Lightly tapping the rear of a car and seeing scrapes appear out of no where on top of the trunk where your car can't even reach is a bit much.