It's a very small section of the seam that runs the full length of the vehicle and up the firewall. Even cut out it's not going to change the crash characteristics of the vehicle. The skid plates, rock rails, etc will change how our vehicle "crumples" a lot more than cutting and/or modifying that seam.
Making it so much more complicated than it is.... 1"x8" piece of metal, lap weld, done.
Edit: just saw the pictures. Not the worst i've seen. Throw a bead down that and don't stress about it.