I bought an Arai TourX (or XD in US speak) a few months ago in the winter sales, and at speeds above 60mph it's bloody awful, noisy and loads of vibration from the peak.
But then I didn't expect any different - it is after all just an MX lid with a visor, and the peak IS going to catch the wind and vibrate - it's simple aerodynamics at the end of the day.
Rather than chopping down the bike's screen, wouldn't it just be a hell of a lot easier just to remove the peak, ie use the helmet the way Arai designed it to be used - with the peak off for fast road riding. Or do some people just prefer the looks and pose value of the 'off-road' style MX lid, over practical considerations like wind noise??
FWIW using my regular Arai Astro R for road riding, I don't have a problem with buffeting at any speed, and find the fairing and screen pretty effective at keeping the worst of the wind/weather at bay on longer trips.
KTM 990 rider and proud of it!!
950 adventure gone, but not forgotten.