How much difference does a strut support across the back make?

 

I found that with a good set of tires (read: tires i felt comfortable pushing to the limit), that the rear strut bar gave the car a bit more rotation in the rear under trail braking situations. It did seem to 'calm' the rear down a bit, making the car more comfortable in slight tail out maneuvers.

Take this all with a grain of salt, in that everyone's driving style is different, and everyone's car setup is different. in my case the car had no suspension modifications.