There are some questions, that, after more than a decade of playing this game, I havn't thought about, until now.

So, what exactly is the effect of destroying subsystems on capital ships? engines is obvious; the others aren't specific. I searched and learned that destroying the weapons system decreases the accuracy of weapons - what's the value of that, exactly? Half? 33%? and the other subsystems don't do anything if destroyed, right?
How does the destruction of the weapon subsystem affect beams, particularly anti-capital ship ones?
Does this apply to AI controlled fighters, too? Can they still fire without a weapons subsystem? Will a bomber's turret still fire if the weapon subsystem is destroyed (albeit with reduced accuracy)?
I also read that a beam cannon can't fire without a sensors subsystem - is that true?
Also, does AWACS actually do anything by default? Does it increase sensor effectiveness in a nebula? If so, how much? Does it do anything against stealthed craft?
and another one - do AI fighters repair subsystems that aren't destroyed, like the player's craft does?