I agree, for pure performance, my recommendation would be a full coil-over with adjustable dampners as well as sway bars. I bought these solely for looks as I felt the car looked hideous for the class of performance.
I don't have experience with non-Performance models, I have to imagine the springs have a more significant performance advantage (albeit not world changing) on those cars than Performance models.
On the RWD, I found that the ~1" drop of the UP Mild springs resulted in a noticeable reduction in body roll. Coil-overs would certainly be better, but for $700 installed, the springs were a good bang for the buck for both aesthetics and performance.