What stacks when casting spells?

[PopeJual]

I know that there are lots of different things you can do/wear to increase your spellcasting power. I see 4 main categories of improvement available for most spells.

A) Chance of Critical (damage spells only)
B) Critical Multiplier (damage spells only)
C) Raw Damage (damage spells only)
D) DC (spells with DC only)
E) Spell Penetration (non-damage spells only)

[whatever] Lore items will improve A and B.
Superior [Ardor/Freeze/Erosion/whatever] improves C.
Efficacy improves C.
Transmutation/Evocation/Abjuration/etc. items improve D.
Spell Focus [school] improves D.
Spell Penetration feats and items improve E.
A/B are also improved by Enhancements you can choose for your arcane spellcaster.
C is improved by Enhancements you can choose for your spellcaster.
E is improved by Enhancements you can choose for your spellcaster.


So my question is, which of these stack?

If I'm about to go into a big fight, should I use clickies for Superior Freeze and Superior Efficacy and wield a Superior Ice Lore item while having my Ice enhancements maxed out if I want the most bang for my spellpoint buck?

Will Superior Freeze override Efficacy and make the Efficacy unimportant?

Will the items replace the improvements to my criticals or improve them even further?

Enquiring minds want to know! (or is this already covered in another thread/article/Wiki entry that I just missed?)

[oweieie]

The general rule is different types of sources stack. The types of sources are items, feats and enhancements. They won't stack with something from the same type of source. So feats don't stack with feats etc. (which is why there is "greater" spell focus etc.) but do stack with enhancements and items. Buffs are classed as items.

Will Superior Freeze override Efficacy and make the Efficacy unimportant?

Don't stack, best is used.

Will the items replace the improvements to my criticals or improve them even further?

Does stack.