The Owner’s manual for my R3T says not to ride over 85 MPH with the factory screen and fogs lights attached as they are not rated for higher speeds. With both the new Mets and new Exedras, I have hit 120 with no headshake. However, when both front tires have been worn down, I get a slight headshake at several speeds above the posted freeway limit (105, 115, 130 mph indicated).
You mentioned a tank slapper in the first post; did you mean a no $hit tank slapper or a several headshake? I don't mean to be contentious, just that my only tank slapper (’06 VMAX) netted me a six week concussion, five broken ribs and a titanium rod holding my left arm together now... Headshakes are pretty unnerving no matter the speed but over the ton do indeed ruin a good pair of shorts...