yes a bit of improvement in turn in feel I think. Here is how Subaru explain the two parts added:
sti flexible tower brace: Revolutionary item developed by STI. The two bars are jointed at the center with a pillow ball bush. With this structure, the bar parries longitudinal forces while holding horizontal forces, resulting in enhanced ground contact of the 4 wheels. As a result, it dramatically improves driving comfort as well as delivering the driver a vibrant and sharp steering response.
sti front support kit: Attached to the front suspension cross-member, the front support kit is made of high quality steel that helps prevent the cross-member from flexing during cornering and improves the contact area of the tyre to the road and improved steering responsiveness. Increasing the body rigidity, handling, stability and comfort of the vehicle. Optimum handling performance is achieved when combined with the use of the STI flexible tower bar.
one suspension mod by it's self doesn't make much of a difference. when you put on mods one at a time , once a month. yeah your not going to notice much.it's a combination of suspension mods results in everything tighting up. tower braces in combination with h brace. then sway bars and then some springs. and if you could do all that in one day , it;s like driving a new car.