pinion snubber or caltracs

i took my car for a spin today [ first time in three years ] ive done alot of changes including new xhd rear springs. when i hammer on it my driveshaft rubs against the tunnel. i had a pinion snubber on years ago and hated it, it was always thumpin while playing on the street. ive had caltracs on a 75 dart and they seemed '' bouncy ''. is there anything else i can do to stop axle twist?