Thats the idea; to reburn crankcase gases instead of venting them into the atmosphere (apparently cleaner).
A breather will keep your throttle body and air pipe clean of oil and will allow your crankcase to breathe better. It may also allow for a slightly cooler inlet air temperature; no more hot crankcase gases being sucked into your turbo. It wont pass smog visual though... :biggrin:
As for breathers, id reccomend Kirbans; its cheaply made, but makes for a snug fit. Poston sells one and is made of billet aluminum, a nice piece, but i've lost 2 of them already in mid-ride; falls right out with engine vibration.