You will have to have the torque box out to remove the floor support and the floor needs to be out to do any of it ,but yes ,support the frame rails and the rockers it is best to have atleast 8 supports / jack stands ,frame rails ,in the front each side at the rear of the frame rail just before the torque box the rocker just behind the torque box and either the rear of the rocker or the end of the rear frame rail