air pressure builds up behind the front tires over 150 mph, getting it light and messy... so they would swiss cheese the fenderwells to first flow thru the front fender then thru the holes at both ends of the doors then finally vent into the rear wheel well.
How much weight lost? Maybe a pound or two. How much pressure relieved? Enough I bet.
Found on https://www.facebook.com/groups/505973489414476/?fref=nf