Had no issues with helmet vibrations until installing the OEM low seat, which seemed to lower my head into an unstable pocket of air. The buffeting was intense enough to blur vision and induce headache after a short period at highway speed. Thought I would have to ditch the low seat or look for an expensive windshield solution. After reading this thread, I ordered the deflector on eBay, and installed with ease only a few days later.
After a 300km road trip, happy to report the buffeting is gone! Such a simple solution for a major improvement in comfort.