The best strut bar designs connect to the A-arm pivot points, or an actual suspension location. Depending on other clearances, they sometimes will bolt to the firewall. Sometimes they are designed, not of round tubing that will flex, but some designs use squared/angled steel to resist flexing. You can read about this on some of my other posts.

The tires, through the A-arms, or through the top of a MacPherson
strut are exerting force to flex the chassis.
You can read this on some of my other posts.

Most strut bars that I see, connect to the top of the shock absorber.
Makes for an easy bolt-on, and plenty of import guys are bolt-on guys instead of build-it guys............ this "top-of-shock" design
probably goes back to when a lot of cars had MacPherson struts,
and back then, the top of the m-strut WAS the top of the shock.
I prefer connecting frame stiffening devices to suspension points.

It's your car, and if you are pleased with the mods you make, then you are the ONLY one that has to be pleased. Catch me at some of the meets/shows, and we can talk suspensions for awhile.-Bob