This is my 1st real build and it shows on some stuff lol, I guess I'm confused about what you're trying to point out ?
Can you point to a photo where you see this please and thank you!
I have some things on my Dart I wish I would have done differently, hindsight is 20/20! Lol
What I was thinking was that basically continuing the front subframe mount all the way back to the crossbar. Pretty much between the two bars you put in, colored it in red in the pic below. Essentially you would have one boxed piece of steel from the front to the rear crossbar. The way it is now you rely on the strength of the welds, in shear, to provide strength on acceleration. When looking at the picture you can see how the forward subframe end could slide back to the crossbar without the welds being there.
Does that help, remember I’m from PBR’s neck of the woods so written word is not our strong suit?