Since nobody appears to be on this forum anymore except spammers may I offer something I've discovered with my C-4.
Some heavily traveled roads develop wear ruts that really feed back into the steering wheel. I've had mine push and pull left and right on certain roads in my area, probably looks like I'm drunk. I do not feel this issue in my F-150 on the same roads.
Don't know if this helps, don't even know what "road walk" is but nobody else is going to offer any advice, hell of a forum, eh?