You need to take it to a shop to have them look at it. Non of this makes much sense. If you are working in the trunk floor being "T boned" isn't going to affect it a whole lot, not unless it was hit at 80 by a truck, and in that case the car would have never seen the light of day. If you have welded stuff in crooked, that can't be fixed by a frame rack, you are back to removing those parts and reinstalling them straight.
Unibodies don't generally twist up like a full framed car when hit.
I am thinking your problem lies with the aftermarket parts not fitting correctly and that is all there is to it. Not cross measuring when installing them, not correcting the poor fit.
What gives you the idea that it is anything like being hit in the side (T boned)? Can you post some photos showing the whole area and then some cross measurements?