what are the benefits of adding Crankcase Air breathers?

[mokomoko]

Yo guys, I have a question:

Does adding a crankcase filtered air breather improve any performance?

For you guys who don't know what it is, here is a pic
http://www.knfilters.com/images/crank_rubberbasesteeltop.jpg

 

[jinkl]

nops no gain

 

[edwin_lcw]

from what i now la your TB wont wear out so fast

 

[mokomoko]

it would be better to add an oil catch tank instead right?