OK, first day of riding with C3 PRO. Some pros and some cons...
It's good, very quit helmet. It envolves your head all arround and you feel safer in it then with any other helmet I owned. Wind noise is dramatically reduced. But, first 50 kms of riding I rode with visor crack open as temperature today was over 30ºC. As soon as I go over 80 km/h I feel slight head shake and it stays there, the same at any speed over 80 km/h. I mean, nothing special, but it's there. Strange, I had no such a thing with my cheap Haisen Flip. But, if I close the visor down, it has no any kind of head shake (buffeting). As it has excellent cooling, probably there is no need to ride with visor crack open.
Anyway, I lowered this evening my Givi Airflow to middle holes, just to see if it makes any difference tomorrow.
I'm hapy with helmet and I know that now I own fiber helmet. All previous ones were policarbonat. Much safer, this one. Also, flip front closing is much stronger then on any other helmet I've owned.