J, I would recommend to you a mild sway bar upgrade. 20mm rear and ~22mm front with poly-bush endlinks like Whiteline would not require swapping the rear mounts and would make a noticeable difference in improved handling and steering feel. Really, this should be your next step since coilovers are out of the question. Sway bars get negative rep because people who are building dedicated track cars are generally better served with stiff springs than the compromise of moderate springs and large, stiff bars. But for your street driven car, it's the ideal solution.
ALK works wonders, but wave goodbye to any thoughts of ever being class competitive, since you're now in F Modified (however, that's an empty class so maybe it would help
). Get the comfort version and it will be an improvement without a massive increase in harshness, though you will be able to notice it.
The Whiteline balljoint kit is pretty new, and I'm tempted to grab one for my own FSP car. The 6Gun kit is way overpriced for a street car, and not a tremendous bargain for race cars either, really.