Breather or not?

[huskyfan23]

Ok, I don't need to go through emissions, so should I get a breather (crankcase) filter that goes into the valve cover? I've heard it can cause detonation but then I heard all it does is add some hp. Which is best/right?

 

[ld50]

I haven`t heard about detonation happening because of it, but the legend is an increase in hp due to the loss of hot air from the crankcase being sucked in the intake.
I`m not sure if it would be noticable tho`....