Umm, 01 M roadster is pointing to the wrong part for the problem in the video. It's part #1. Part #8 shouldn't whistle with the top down.
The problem is that air gets between the glass and the front edge of part #1 and makes a sound like the childhood trick of blowing a wide blade of grass between your thumbs. It's a reed vibration type of noise. Carpet tape worked for me, but if you don't plan on replacing part #1 anytime soon (windshield is in good shape), I'd use Permatex 81158 (black) or 80050 (clear).
2002 M roadster