Aerodynamics being my biz, I am intrigued by these windshields. The factory design moving the windshield forward of the fairing is the same idea as a slotted flap or slat on an airplane wing, allowing high energy air to move to the backside and promote smooth airflow on the low pressure side. Instead of creating a big vacuum bubble behind the windshield where the air then mixes turbulently with the air rushing past outside the bubble, it all moves smoothly. Even though there is shear there is no turbulence.
I find that as I sit ever higher and even stand a bit, the force of the wind increases on my helmet but there is no turbulence zone. Kawi did good, and with just a bit more engineering (rather than styling) they could have had a fantastic stock windshield. The aftermarket has given us a number of excellent products to choose from.
When I rode in the rain, the drops on the inside of the windshield were moving downward with a slight breeze pushing them. There is some kind of reverse direction eddy current next to the inside surface. Fascinating!