Can easily be removed. Options I have seen are to seal in with perspex (no ventilation), cover with mesh or do a reversed wrx scoop.

In theory it should help draw hot air out of the engine bay and encourage air to flow through the radiator. Not sure how roadworthy it is though. Rear facing scoops without anything to prevent engine bay leakage finding its way onto your windscreen are definately out. Prety sure meshed in holes are too. Think if you take the covers off the mesh panels either side of the boonet at the front you are un road worthy.