I chose to leave my lower inner hinge pin screws as steel (Xray T2). I've bent quite a few of those, so going Al is a guaranteed disaster. I also had my battery strap switched to Al screws, but in a head-on crash with heavy track borders I sheared a lower countersunk one. Other than that, I haven't broken any others.
The M3 countersunk screw also uses a 2mm hex.