some armor-related questions

file armours_gc.xml, what do these attributes exactly mean:

<Special heavy="1" strength="80" />

<PsionicDefence defence="80" points="20" degradation="3" />

Heavy means it can use only heavy weapons, the final line at weapons.xml... i didnt see strength at that line or i didnt look so detailed..

<PsionicDefence defence="80" points="20" degradation="3" />

kabill explained it to me.. but my brain is at near death state because of uncontroled mod balancing..

The Guide for Modders will tell you all you need to know re. PsionicDefence

nice, TY!

so the only attribute under question is "strength" for the predator armor, tried to change it randomly - no visible effect

The heavy property isn't actually the use of heavy weapons only (or if it is, it only applies in ground combat). I think that's used to make the armour 'heavy' for the purposes of smashing through things like doors. To limit armour to heavy weapons only you need to add the line:

<biggunsonly/>

to the armour entry in armour.xml (not armour_gc.xml).

The strength property is the value a soldier's strength attribute is set to by the armour. Make sure it matches the value given in armour.xml also.

For the psionic defence values:

Defence is the level of psionic strength the armour protects against (any psionic attack at that strength or lower will be shielded against and therefore ignored)

Points and degredation indicate the number of attacks the armour protects against - every time the armour protects the soldier the Points value is reduced by the Degredation value until the Points value is at 0 after which it no longer offers protection.

EDIT: It's possible the strength value there doesn't do anything; it might only be the value is armour.xml which matters.