Upgrading a Fairly Stock Suspension

Now will there be a noticeable change in handling (granted with better wheels and tires) between the Hellwig 1-1/8 bar, Firm Feel's 1-1/4 bar, and Hotchkis's 1-1/2 bar?

I am going to go with the Hellwig bar. Dave is a contributing member of this board and he recommended this bar for my car.

http://www.summitracing.com/parts/hel-55906