Well, more a matter of roll stiffness correction than self levelling and dealing with a sprung system, the removal of the rear ARB is going to reduce it. More overall roll will reduce the load on the front when cornering and with it, grip. Doing the same at the back would potentially reduce both grip and traction for the same reason which is why racing cars use thicker bars. Not sure I can see a tangible advantage over changing the bushes every ten years. Drop links rattle when they are loose. They are easy to change and not expensive. ARBs are not always necessary at the front, lots of cars don't have them but when a chassis has been tuned for handling by smarter people than me, I reckon to mess with it at my peril.