I recently installed the Koni Sport Struts/Shocks and the BMR rear sway bar on my Mustang. Both mods significantly improved the ride and handling on my vehicle. Very happy with these mods. :D
I have had manuals in the past and currently have an 07 GT Auto. What I did notice was that after I installed the CAI and had a Custom Dyno Tune it made a big difference. The car feels much livelier and responsive.