On all of the bikes I owned the only fight I had was against buffeting, not the noise. So all of the changes on my 3 V-Stroms were different mirrors, mirror extensions and Givi Airflow. That solved buffeting 100%.
But on my previous '14 DL1000 and actual '18 DL1000 new problem appeared: huge wind stream hitting my belly, then rising and entering with high pressure into my helmet from below. My eyes were watering all the time and different helmets didn't help. So it led me to another installation, wind flaps from BMW GS. I only modified them slightly to fit them right and the problem was solved back in 2014. Later transfered them to my '18 model.