Subframe connectors for a driver/cruiser, necessary to weld to floor?

2 X 3 X .125 wall tube used here...........
Weld In Your Own Frame Connectors (archive.org)

I was thinking I would buy the steel 2x2 and fabricate them, just welding the ends to the subframes.

I used the method in the posted link, they work great, I saw a noticeable difference. Fairly easy to do. Just make sure your car is level and secure before you start. Check the doors after it is set and see how they open and close, if happy then have at it.