I tried them a few years ago, and they sort of worked, reduced the vibration, or at least lowered the frequency of the "buzz". They're not a total ripoff, but also not a perfect solution. Like many things. I ran handlebar mirrors for years on a GL650 with a Vetter fairing, and my current bike, a GL650I with fairing mount OEM mirrors is much better. Mirror position, field of view, little to no vibration, good on all counts. Well synced carbs, balanced tires, etc. can help too. Aftermarket fairing mount mirrors are often reported as being inferior on several counts.