I have the medium calsci shield. The airflow is smoother with it down than the stock shield but its also taller in the down position . I don't notice the big difference everyone talks about as far as noise and buffeting. My wife feels no difference on the back and thinks it was a waste of money. I also liked being able to see over the stock shield in the down position. I have to sit up as tall as I can to see over the calsci and then I can just see over it. All in all a toss-up for me.