I did a 10,000 mile trip, coast to coast and down the west coast. I put a brand new set of Torrence Next tires on, and used Dyna Beads for balancing, before my trip and was more than pleased with them. At times, I did hit speeds, a little on the 90+ side(crossed Nevada on Rt 80, always over 80). I never had the slightest bid of instability at all. The more I went over 80 mph, the more, the stock windshields upper half, would vibrate, making my Nuvi, shake like a dog, hitting cinnamon seeds. It was a subliminal reminder to slow down.
I have a set of Jessie 10" bags and center box, mounted on the V2, which surprisingly don't seem to cause any problems, even at high speeds. I also have a 2012 Wee, Adventure model, which does get head shake while decelerating, even within speed limits. I feel the racks that came with it, might be flimsy and part of the problem. It doesn't have a problem when the bags of off.