I'm in the process of replacing my floor pans and most of the subframe due to some serious rust damage. I'm cutting out most of what I need from a donor car, but will welding in part of subframe compromise the structure? If so, what would be some good ways to provide extra support? SFC's are definitely on the list, and I've already decided to essentially delete the back seats I was thinking X-bracing under the floor pans perhaps? I don't want to got the route of swapping everything over to a clean shell, so any alternative suggestions you guys have would be great!

Also, The areas I've circled in red on the attached image are indeed parts of the subframe, yes?

Thanks,
Jack

 

The photos didnt show up

 

Forgot the pic lol, not my car but it works for the imagery.