Argen, You are already running my "hot tip" (and the one thing that sorted my car!) for stopping grip roll on carpet!!!
However, a couple of suggestions that might help. You are creating an imbalence with the roll bars, the front one is too stiff, and nothing on the back probably isn't good. I ran 1.5mm all round.
Rear toe-in, not sure there should be any need to have extra at the hub. We usually just run the alloy block.
Yo don't say what position you are running the cells, if not max in then try that as the weight doesn't move about as much.
A touch less camber (0.5 deg) all round might help.