Breather filter question

My friend was just looking at a book I have in my bedroom about cars and performance and came across a section about breather filters. He asked me about my car and all I could do is explain how it works.

I have a N/A by the way, it's the same hose that connects to the all TT's T pipe.

I know you can put one where the hose from the intake pipe is, but what about the front? Does it need one or no?

Thanks.

Bump because I'm still curious...