I made some changes to the force feedback effects file, since there seemed to be an error in the code, creating a somewhat gravelly feeling in the tarmac texture.
Try my revised effects file and see what you think!
I use the following vibration settings in game:
Vibration Strength: 50%
Wheel Strength: 100%
Wheel Weight: 50%
Simply unzip this file and put it in your forcefeedback folder in Autosport. Make a backup of your effectsetup.xml file first, just in case you want to revert to the original file, although I cannot think why you would!
Hopefully this can make your Autosport experience even more fun!