[FRED/LI]

Considering where you are, and the heat of the desert, you need all the available air flow. That shield makes it just a little more difficult to exit the fan's airflow. Coupled with the heat coming off your roads, it warrants removal.
Hope to make a long run this year with mine to your city for a stay with grandkids. Often wondered what the heat would do to the 993. Will find out.
Oh...the reason for the shield was Swiss noise level restrictions.
Aerodynamix? Maybe at top speed. Read somewhere that the race cars did not have them installed.
Another observation...the heat sensored cooling fan operation when the engine is turned off was added when the shields came about. Perhaps they recognized the potential danger then.