Allyn, the backdraft wind is blocked with the Windbaffle panel.
It helps reduce cocpit turbulence, hence less hair tossing and less wind roar at highway speeds.
Also you can keep the cocckpit warm or cool as needed using your heat or A/C as needed.
Keeping the windows part way or all the way up can help you finetune airflow in the car. Bob's trick using the dash vents at high flow help at extra- high velocities.
Bill, since the wind comes from behind, placing the WB panel behind the rollbars allows it to be pressed into the bars, but either position is secure.
We have no had vibration problem with the black standard Velro strap or with the clear vinyl straps with clear mushroom (industrial) Velcro clasps.