If your question is about the breather itself....

Some people that run intercoolers have blocked off the port for the PCV, there for pressure builds up in the engine and starts blowing oil out from the valve covers and filler cap....The way to release the air is to install a breather. This will neutralize the positive and negative pressure in the engine (same thing the PCV does).

Botton line is if you dont block the PCV, you dont need a breather.

webracin