Without making changes to the geometry of your suspension then lowering it too much will not make your car handle any better.
The factory is not stupid nad they generally design the suspension to work correctly at the height they set the car. Hence after lowering you will possibly need to put in some RCAs up front nad if you keep going lower you will need to change the mounting points on the rear end.
However if you don't really car about having a nice low car that handles like crap then just lower it with something like the king springs.
I use Koni adjustables myself, but they were not intended for a compromising ride.