Gents, there is a file under steamapps: assettocorsa\system\cfg\damage_displayer.ini
which has this in it:
[MAIN]
TIME=4
MAX_DAMAGE_KMH=60
POSITION_X=20
DISTANCE_FROM_CENTER_Y=-200
If you don't like the damage display, you could try changing some things to turn it off, like make TIME=0 perhaps, or change the KMH or position. I haven't had a chance to play with this yet.