The thing is these cases are designed with airflow in minde, so when you cut holes anywhere you change the direction air moves inside, and how it cools differnt components.
So this might lower the "chip" that does the main job's work, and keep it cooler and less noisy, but the "cost" is other places in the console might be hotter now (which could be bad).
Also you shouldnt keep it right next to a big speaker...... imo.
In this case you are wrong. PS3 cooler cools the cpu chip, then the air flows to cool the gpu chip, and finally it flows to cool the psu. The problem with original design is that the fresh air is taken only from small vents on the sides of the ps3, and with time these vents get blocked by dust. when it happens, the fresh air tries to get in where the bluray drive is, that's why it gets dusty too. When you drill these holes like I have done, cpu/gpu/psu temps decrease quite significantly, it is shown in this video https://www.youtube.com/watch?v=MntWREt3euA&t=1830s
the video is stupidly long but u can jump to see the important parts.