Ehhhhh your car is probably jumping because of wear in the suspension links in the rear usually its the bottom push link. This seems to me more likely since you have such a wide setup. Or your shocks maybe going. You may want to check any of these professionally before you invest in a staggered setup because the problem will just simply remain. More rubber won't help.
I am sure the people on this thread would agree....
Hope this helps.


ps. Nice to see you here Lee