What are you doing to the 'vertical' portions of the cross member, where you've trimmed it to make room for the trans? That's where the strength for accommodating torsion bar loads comes from.
See the post right above yours. 1/4" thick plate bent into a hoop that will be welded in place of what I cut out. It will be welded to the top of the tunnel, on the sides, and to the ends of where I cut the original out at the bottom on both sides