k-frame strengthening

1. There was a comment at the beginning about Mig vs Tig. I'm a Certified Tig Welder, welding for over 50 years. I would not Tig these K members, takes up too much time and introduces too much heat with resultant warpage potential of the K member. You need some amps to get decent penetration of this size metal piece.
2. My first suggestion after a deep cleaning/soaking/sandblasting/etc, would be first to triple? up the existing OEM spot welds. They structurally IMO add more stiffness to the member by being closer to a node point of the joined pieces than full edge welding of all the seams achieves.
3. After the spot weld additions, then weld the seams
4. The LCA mods have been addressed elsewhere and are IMO just another example of feel good Automotive OCD and no more