If you’re adding frame connectors, you may not need to go through all that trouble of welding in the cross brace mounts.
Personally, I think I’d pass on that project. Unless you plan on doing some serious pedal mashing with some really sticky rear tires...
I'm having the debate with myself whether it's worth installing them and repainting the bottom of the car. I've got the Hotchkiss subframe connectors and the L braces I ordered 3 weeks ago are still back-ordered. Just finished swapping a 416 LS stroker and 4L80e into the car and I want to drive it. Just don't want to destroy it, but I'm thinking the subframe connectors are providing way more support and rigidity than those L-brackets and x-brace ever would have.