Airflow is probably unaffected at normal speeds. The depression in the rear deck creates such a huge low-pressure area behind the cab that airflow from under the car is sucked out regardless of whether the windows are there or not. In addition, the Pantera body sides generates a boundary layer estimated at 6" deep around the rear 1/4 windows, so again, there is no appreciable airflow either in or out any side holes up to about 150mph. There are two 'air scoops' sold- one about 3" deep, one (so-called elephant-ears) about 5" deep, both secured to the window frames. The 5" one does gather some ram-air at least above 150. The window frames are not secured to the body. Only friction between body & rubber gasket hold them in. One racer ripped his left window frame/elephant-ear scoop out at 175 mph- cost him a bundle to replace. Scoops there are probably not worth the cost but needs wind tunnel testing to be sure.
