Just in case anyone wonders about how resonant frequency with wind can really affect things ...If you hit the right resonant frequency with a combination of speed and wind it does vibrate.
I have seen it on my hood as well. As mentioned it's a lighter weight aluminum hood. It is built to flex so no worries, though it does make you feel uneasy when you first see it!
The hood ripple caused by the ram air scoop will not be fixed by adjusting the bump stops. The ripple is actually mid-hood, but, because of the height, length and curvature of the hood, it seems like it's the whole thing.I experienced this too, and also posted a thread on it. Was concerned when I first noticed it. Had to pull over to make sure the hood was latched on correctly, and it was. I haven't adjusted the bumper stops yet to see if that fixes anything.
It’s not actually flopping! This has been bothering me for months and I finally figured it out.