I recently read a great article on crankcase breathing but just spent arf hour looking for it with no success.
What d'you mean by 'race' breather? A race breather system will feed to an expansion box fitted on the subframe, and some sort of reed valve at the crankcase.
The dude writing the article was saying that them little cylinder shaped jobbies that sit lonesome on the crankcase are not recommended - they become soaked in oil vapour which then leaks out over the back of the engine/tyre.
If anyone knows the writeup i'm on about and can post a link that'd be fab - it's a step-by-step project of converting a 996 to a proper race breather system.