As Stainless wrote, the roll cage size increase to get more space for the helmet.
This did not effect the frontal area that much, as the bump in the old cover for the engine compartment was larger, anyway.
so, here some numbers.
the frontal area is app. 3 percent smaller than the old one
the drag, if the rough simulation is right, will be 12 percent less
two other number changed also, here we have to see what it means for the handling
the downforce from the airflow over the body is less than the old one
and the CP moves about 5 inches forward.....
with the cleaner airflow the car will be better controlled by the airflow to go straight...
it is a plus and minus....the white dyno will tell what the real increase of speed will be
but finally the condition of the salt surface has to be right to turn the advantage of the improvements into speed