I suspect that the lower screen is for faster driving offering lower wind resistance, but I'll be a "cruiser" around Santa Monica and L.A. and would probably not get on the freeway with the Enertia Plus. The L.A. freeways are just nutty. Maybe will ride on the Pacific Coast Highway up to Malibu which would require a speed of 45 to 50 mph.
I'd like a full screen/cowl that covers the handle bars as well.