I wish the armor mods worked a little better, I would love to make a stealth-ish FAS, but all of my tested failed. Just couldn't get it to work for me. Armor is the last line before your dead, it shouldn't be your first defense, no matter how much you got.
Any average PVP will just aim your modules.
Dual chaff and FA off will make most other ships unable to hit the FAS let alone a module when silent running. I think the FAS was designed to 'go naked' but it is high stakes, especially as an all A build is around 80m.