I think it may bewind buffeting around those big mirrors. There is a company called 034 motorsports. They sell a universal anti buffeting kit. It’s only 15 bucks. I ordered one. Let’s see. Wind buffeting occurs a lot on other vehicles with stalk mounted mirrors. Very common.
Hi
Have you tried vortex generators on your mirrors. It seems other manufacturers have similar issues with wind buffeting at high speeds around the mirrors. My Son’s GTI has vortex generators on the mirrors as standard.