Now here is what I plan on doing. First of all I will be replacing the noise fan in my PSU (Rosewill D600 stallion edition) with a better one. But I also want to add another 140mm into the 5.25 x3 bays on the front.
My real question is should I cover the holes in my side panel? Will this create a better airflow coming from the front then exhausting out the top/back of my case? Also would it be worth replacing the fans that came with the case. They seem to work fairly well as it is.
I don't have the option of mounting a side fan because my CPU cooler is massive and barely fits as it is. I could mount a fan on the outside of the case, but it would look kind of ghetto xD.
Unfortunately, I am not too sure if your case will be compatible with a 140MM fan. I've owned a Rosewill Blackbone in the future (brother has it now) and it only has a mount for a 120MM fan.
From my personal experience, covering the holes in the side won't provide better airflow, but will make your internal ambient temperatures a little bit hotter I would just leave it as is! (Though, you might want to cover it up with a bit of mesh..I remember this was my primary intake of dust when I used the Blackbone