help with cupcake recipe!

This recipe is perfect,but I would like to make a small modification, and that is to add a small amount of cocoa powder (2-3 tablespoons).  If I were to add cocoa powder to the recipe, would it change the texture and consistency of the batter or because the amount of cocoa powder I want to add is in my opinion, a small amount, not make any major changes in the texture of the cupcakes?

If adding cocoa powder would change the texture/consistency of the batter, what changes would I have to make to the recipe to keep the texture/consistency of the cupcakes the same?

http://allrecipes.co.uk/recipe/23955/wickedly-dark-chocolate-and-chilli-cupcakes.aspx