While I seem to be a little late to thread. The crash protection for cab is pretty good as its built from factory. On the way to Charleston(heading to Iraq back in 2002)we had a LMTV rear end another vehicle. The front of cab was pushed in but we were able to still drive it. We had to jump the K1 relay to start it but it still ran just fine. I've also seen a few roll on their side when operators were driving way too fast for a corner and it did push A-pillar back but no one was seriously injured. So I guess I'm saying it's a very safe cab. It weighs 3300 lbs by itself.
You may want to check out steelsoldiers.com for vehicle specific info.
GLWB!