I had a strut bar on my two last cars- Miata and Kia Forte Koup - I didn't notice one bit of a difference either. I am sure at the track it would help, but for regular daily driving...I don't think it changes anything.
if you drive on pothole infesdted roads the bar will keep the car from being a rattlebox in a few years. i put them in all my cars just to keep them feeling new and not beat up after a few hard years on the road.
I looked closely at my car and pictures of installed top-mount bars from multiple manufacturers. The mounting holes for these bars are about a foot forward of where my car's strut towers are located. The mounting holes appear to be body panels rather than the frame. How can this possibly improve my Fiat's handling? I really like the looks, but I'm not grasping the mechanics of this mod.
On cars that have the strut towers away from the firewall and in a location that allows for flex under cornering, a strut bar makes sense.
The Fiat 500 has located the strut tower right next to the firewall/safety cell of the car so no real noticeable gain in handling dynamics would be achieved by adding a structural bar up in front of the suspension mounting points.
They will however increase rigidity a little in the frontal area, and that might minimize rattles.