Mithral Fluidity( Eberron Campaign Setting, p. 57)
Your movements are smoother and more fluid than those of other warforged.
Mithral Body (ECS) , Warforged,
The maximum Dexterity bonus a warforged with the Mithral Body feat can apply to Armor Class is increased by 1. In addition, the armor check penalties to Balance, Climb, Escape Artist, Hide, Jump, Move Silently, Sleight of Hand, and Tumble checks are reduced by 1.
This feat can be taken multiple times. However, armor check penalties cannot be reduced to less than +0.