For a daily driver, a strut tower brace doesn't do crap. I've been in cars with them and without them and I can tell you they don't make a lick of difference for the types of driving you do on public roads. Even if you're nailing it and taking the corners quick. You'd have to be taking the car right to the limit to notice anything like body flex.
If you want to improve the handling on your Sonata you'd be better off looking into a larger sway bar. If they make one. The 2011 Sonata is brand new so I don't know what if any upgrade parts they make for it. You could also swap out any rubber bushings for poly urethane. It's stiffer and doesn't flex as much. Things like end links, sway bar bracket bushings,strut rod bushings are pretty easy to swap out for poly.
It will make your ride harsher though. So be forewarned. You sacrifice ride comfort for performance. Can't have your cake and eat it too. Don't forget to get the alignment checked after you mess with the suspension too.