[Christ]

I wonder primarily for the case where the tires don't come out to the outer edges of the car (most OEM configs) and there is no stippling or any kind of aero-modding to the rear of the wheel opening to lessen it's effect on the (now-separated) airflow.

Obviously, if domed isn't any better, just making them wide enough to meet the outer edge of the vehicle must be, as this would mimic the obvious benefits of fender skirting without the obvious problems associated with skirting the front wheel openings.

Essentially -
Less open area = less airflow disruption
Less depth between surfaces = less airflow detachment.

A+B=C, so less airflow disruption + less airflow detachment = smoother flow?

Just a thought, at 0519hrs, after being sick for 3 days and not sleeping the last 23 hours or so.... maybe I'm legally insane at this point.