That shroud surely hinders airflow at higher speeds, but removing it will no doubt cause hot issues at idle and cruise speeds imo.
I would look into fabbing some one-way flaps in the shroud which open up when the airflow into the shroud demands it.
this seems like a great idea. cut pieces out of the biggest areas in the shroud and install a small hinge or two on the top of the pieces so the swing open at speed.
