I have said oil seporators because they are very cheap and easy to replace and will improve your oil consumption. Also think about it this way, if you have got oil in the plenums there is only on way it could be getting in there, the oil seporators! I am not saying this will fix everything because it sounds to me like you may have more than one problem. But my advice not only to you but to everybody on this board is if you have not already changed you OS then change them, it can't hurt you, the car or your wallet. Simple.