The 'max Dex' refers to how much the armor limits the Dex bonus (which, IIRC, also limits your reflex saves, too--D20 guru RedHawke
can correct me on all this). Your defense is determined by your armor bonus and your dex bonus.
So, if your Dex bonus is +6, and the max Dex allowed by your armor is only +4, then only +4 of your Dex bonus will be applied to your defense.
When you're adding your Wis bonus to your defense, it's treated as a Dex bonus for purposes of defense.
Originally Posted by Irian
If this is true, the Jal Shey Robe gibts me +4 (Dex + Wisdom) and +4 Defense (Armor). But the Jedi Knight Robe gives me +10 (Dex + Wisdom) and +2 Defense (Armor)...
The formula is Defense=Base defense + armor bonus + Dex bonus (capped at the Max Dex number)
Let's say your base defense with no armor and no dex bonus is 20.
Now, let's assume you have a +3 Dex bonus. Your defense becomes 23.
If you add the Jal Shey armor, you get the +4 to defense, which would make it 27 (your base defense + Dex bonus + armor bonus).
Now, you've added your Wis bonus to your Dex for Defense. Your new 'Dex bonus' for purposes of Defense is now +10.
So with the Jal Shey armor your new Defense is 20+4 (for the armor bonus) + 4 ("Dex" bonus) for a total of 28. You can't apply the full +10 Dex+Wis bonus because the Max Dex allowed is only +4. So, you're losing +6 of your possible Dex/Wis bonus.
With the Jedi robes, there is no Max Dex penalty.
So your Defense is the base (20 for this example) + 2 (armor bonus) + 10 (for Dex/Wis--you can apply the full amount since there's no Max Dex penalty), so in this case your Defense total is 32.
So in this case with the Jedi robe, you lose 2 to your armor bonus, but you gain 6 for the Dex/Wis bonus, so you come out ahead.