Andy ,
not speaking of Belgian "pavé" but secondary concrete/asphalt roads with putholes... were modern cars were driving "as" normal , i know, i my BMW530 , it are noises as " bamps " but not steering effects ... The GTN jumps and scary directs a angle... ok, at 80/90 mph , but modern cars with family aboard don't seem that afraid... couldn't follow them with piece of mind !