Is Clothing considered armor...?

[Hypersmurf]

They grant an armour bonus, in exactly the same way as armour itself does. Which means I then enchant them with an enhancement to their ac. I end up with +5 bracers of armour +8, for a total of +13 ac.

Ah. No. An enhancement bonus does not increase "an armor bonus", it increases "Armor's bonus". As in, the armor bonus of armor. Bracers of Armor provide an armor bonus, but they are not armor, so you cannot apply an enhancement bonus to the armor bonus of the bracers.

So - Bracers of armor +8, +5 padded armour. Apparently the 'enhancement bonus' on the armour stacks with regular armor bonuses... Total of 13 AC.

Firstly, I'd dispute terming the armor bonus provided by Bracers a "regular" armor bonus.

But the SRD quote is loosely worded, and doesn't - in isolation - adequately express what's happening.

An enhancement bonus on a suit of armor does not, exactly, "stack" with the armor bonus in the sense that the word is usually used. The armor bonus modifies AC; the enhancement bonus does not. What the enhancement bonus does it to change the armor bonus of the suit of armor.

Padded armor gives a +1 armor bonus that does not stack with +8 Bracers. +5 Padded armor gives a +6 armor bonus - the +1 armor bonus modified by the +5 enhancement bonus - that does not stack with the +8 Bracers.

In a sense, the enhancement bonus "stacks" with the armor bonus... but only the "regular" armor bonus of the suit of armor to which it is applied.

-Hyp.