Question: How can I unlock cheats in Max Payne 3?  If I turn them on, can I still generate stats and earn trophies/achievements?  If not, are stats and achievements permanently disabled for that save file?

Answer: To see what legitimate cheats are available in Single Player, go to Chapter Select in Story Mode.  Scrolling through the cheats will cause a description to appear for how to unlock it.

While you are using cheats, stat submissions and trophies/achievements will be disabled.  However, you can play without cheats again and resume earning stats and trophies/achievements.