I had a similar experience. Bike ran fine even when driven hard in going in & out of corners. Under warranty the dealer had to replace my damaged wheel, tire, rotors etc. They tried to go beyond by replacing a motor mount and installed new swingarm bushings. I rode the bike home and noticed a slight wobble coming from the rear. It took me some time but I finally found the swingarm bushings were not even tightened. I torqued them to the factory recommendations and the problem disappeared. Get a service manual for the correct procedure for removing, inspecting and installing them. Or pay someone that you trust that will get the job done correctly. If it ran fine and the wobble just started I would not recommend a brace at this time. Get it back to the condition it should be & then you can look at braces. I have one but I have the 08 frame. Did you make any changes to your suspension or lower your bike by any chance?