In my case, I never had a wobble nor did I think my bike handled bad. 08 SERK. But after my friend bought his 09 SERG and riding it through the mountain turns etc, I felt my bike didn't track nearly as straight. I really was not feeling comfortable trying to follow him up the canyon at the speeds he was going, I felt somewhat pushing it, He appeared to be having no trouble keeping the speeds he was.
So I have been reading all the stuff about all these braces etc. didn't think $300 would break my bank, so I bought one. I doubted the 09' Frame really would handle much better, but it seemed to be a nice improvement.
I looked at my cupped front tire and changed it over the the Dunlop E3, rode it seemed better, but not quite the same as the SERG.
The front forks don't dive on the SERG either, I changed my fork oil to the heavier oil after riding his bike, I did also like that better too. Both bikes have similar tires/sizes. I think the forks have something different in them (a oil valve restrictor, or something, not sure what its called? I looked at the parts book and it shows it. I think this has something to do with the fairing on the SERG. Anyway, the oil was cheap and I liked the results.
I put the bagger brace on, went out an rode it, took it up to 110mph was waiting to feel a major difference, I didn't. Probably because going straight or at high speed, I never had a problem before.
I rode it a few hundred miles, felt better overall when turning around town type stuff. Then I went riding in the mountains with a lot of turns etc. I felt like the bike tracked in the turns much better. Pretty much like the SERG did. It just holds the twisty turns better. Then I rode two up for a 140 mile ride through the mountains ( same roads, I have been on before solo without the brace ) I really thought it handled much better. I think I noticed when two up I felt the most improvement. I believe I had more of a "Rear Steer" type thing than anything else, and the brace stops that.
I am happy with the way it is now, I believe it improved the way it tracks. It didn't cost that much, was easy to install and overall it was worth doing for me.