The front of the lower A-arm is what I and others call a kneeling pivot point. If you look closely, the pivot is essentially double jointed and does not merely move in one arc. Ford did this to offer a softer, smoother ride yet if does compromise handling especially under hard corner braking. Note that Ford dropped this IIRC after the '64 model year and for good reason.
The kit eliminates this double action and does improve handling....a lot! Yet, for a pure street car never driven hard into corners, etc., I'd skip it.
