catch can setups (what's right and what's wrong)

[doridoridori]

as title states i'm trying to see a few different setups to do mine properly. I know from factory there's the stock catch can comes off of the "T" fitting, the other hose goes from the "T" into the intake tube on the turbo before the MAF sensor. I have however seen setups where people remove the intake tube off of the turbo and run a small filter on the end (I imagine oil to seep out over time). What is right and what's wrong? will the filter hurt anything ? I'm new to SR's so spare me I just haven't heard anything concrete.