Just updating some info in case anyone in the future is looking for it. I weighed the stock pulley. It weighed in at 4lbs 13.1oz (I'm sure this is posted up somewhere).
So you get a savings of 3lbs and 13.1oz. Not too bad.
The sizes do not seem that far off. Here are a couple of pics of the stock pulley vs the Ebay Bomz pulley.
Now that I have gotten some practice changing out the pulleys, I can go to the dyno and test them out. Hp/Torque readings may be different than before since I have a different set of wheels on the car. That's all for now.