From what I understand KDSS allows for the decoupling of the sway bars. As such the nose dive under breaking and nose lift under acceleration is the same on KDSS and non KDSS as KDSS only affects the roll stiffness of the sway bars being coupled or non coupled.
If you want dive and squat control then it is the XRES system found on the Limited trim level. Where the front and rear suspension (shock absorbers specifically) are tied together hydraulically.
Go drive brand new versions of both. You'll feel the difference. The difference is not just roll stiffness.