We did have a thread on this about a year or so ago. Someone had pics of late dart with what looked to be factory diagonal braces. To me the factory ones looked a bit flimsy.
I can't tell you how much they would help (if any) but I'm sure they wouldn't hurt anything if you want to fab up a set and give them a try.
Just my opinion... But if they were effective on an A-Body someone would be making/selling them by now and I never see them offered.