Hmm don't know if explained it well, assumed you would have felt this or understood.
Say going through a corner, then coming back onto a straight pulling hard. The rear axle feels like its at full extent one way, then when you pull through hard on the straight on corner exit the beam feels like it rips hard the other way quite violently. Feels disconected like riding on a trolly dolly. Rear arb + rear bush's I don't get this anymore. Rear bush's make it feel tight at low speeds, but rear arb stops fidgety rear end feeling whilst tyres still in contact with tarmac mind!
My opinion.. Bushes good low speed daily differences felt, rear arb felt more at speed & pushing even further. Both are good mods, doubt will be disappointed if did both mind