imrellik, don't increase the eggs. Increasing the eggs gives you a brownie that will more resemble a cake.
I don't like chocolate, but brownies are my boyfriend's family favorite, so I make them.
The recipe I use for fudge brownies has the same ratio of unsweetened chocolate, eggs and flour (100% of each), two and a half times the amount of sugar (250%), and 112% of butter, which is pretty much what the recipe SCP gave you has.
I get dense, fudgy brownies with that recipe, much like the Fat Witch ones. At the office, for a few years, every person got sent a box of the mini Fat Witch Brownies for their birthday...so I know those well.
More butter to flour = dense and fudgy
Less butter to flour = cake-y
Your recipe only has about 3 oz of butter for about 4.5 oz of flour, which is less butter than you want.
So maybe make the recipe SCP gave you, which comes from a reputable place, and you'll get what you want.