Yea...3mm should be plenty. I'm only getting it as a preventative measure to the new X-Braces bending.
I didn't have a "dumb crash" - All my spills were extremely light. Just a few over-jumps there (not really a crash), and few underjumps here - landed on wheels, so it should have been fine. The only time the truck had an incident was just flipping from cornering too fast or something. There was no "slam into the wall at the end of the straight" incidents.
Also, no one has ever bent both X-Braces. I've actually only ever heard of two X-Braces being damaged, each time just one broke. The first was because of an overtightened screw that contorted it. The second was someone ran it with one of the lower screws only 1/2 threaded in, and it got caught on something and bent it like that.
I've never actually heard of someone damaging one from a crash.
You should never ever get a "bad batch" of metal. Its nearly impossible to buy metals without certification, and I doubt the do this. So either its a bad batch and you can simply sue the metal manufacture for false certification and easily win.....or you crashed the truck. Doesnt matter if you think it was a bad crash, it was obviously bad enough to bend parts. Parts bend when they are pushed beyond the limits and thats it. If you dont think it should have bent, then the part wasnt properly engineered for your application.