The way the front strut bar works is when one wheel/strut compresses, it transfers that force to the other strut, which improves stability. However, as you said, when you go over a speed bump, both struts compress, and therefore the bar ends up making it feel stiffer.
In terms of what to do to help the car driving wise without making the ride too harsh, I would go for the rear UR tower brace. The front of our cars is already decently composed, however the rear is another story, and kind of lacking stock. The tower brace helps a lot. Although for a certain level of handling, you will have to sacrifice some comfort, and maybe go a little slower over those speed bumps, because I have the strut bar and 18s and if you're hitting a speed bump hard enough to get a "thud" you;re close to(or already) going fast enough to damage your front suspension.
In terms of what to do to help the car driving wise without making the ride too harsh, I would go for the rear UR tower brace. The front of our cars is already decently composed, however the rear is another story, and kind of lacking stock. The tower brace helps a lot. Although for a certain level of handling, you will have to sacrifice some comfort, and maybe go a little slower over those speed bumps, because I have the strut bar and 18s and if you're hitting a speed bump hard enough to get a "thud" you;re close to(or already) going fast enough to damage your front suspension.