Well, Yes and No. It won't bring in more to your intakes unless customized to be able to scoop in that extra airflow. How ever what it will do is allow more air to travel threw, and around your engine bay. Were the car stands right now, the air flow threw and around the engine/ exhaust maniflod is really minimal. I think that a mesh grill may, or may not help. I think the lower grill would be beatter if they didn't make that solid piece so big. I understand it may be to protect some of your components, but I say cover them internally, and leave the front end open for business.
I myself removed mine ,and HDDP's front port holes as well. And your right, it opened it up to about 4.25" around. It greatly improved for us. I really noticed a responce, I think it has to do with how I made my heat sheild for my filters. I designed it in a way, so it works as scoop, and deflects the heat from thos exhaust maniflods. **** do they get hot. man I have a many scars from burning my arms on them while tying to work on the car.