Oh man! I wish I could remember all that I learned about this...
I went with a simple air filter do-hickey mounted to the nipple on the valve cover and don't worry about it. I've been told that you can plumb the separator in with no problems. I also found one source that instructed me to build a "road-draft pipe". Evidently, older cars had them. In what I read, They are the reason that, back in the day, you'd see a dark line down the middle of the lane on the highway. What it is, is a tube that runs from the nipple on the valve cover, down to a low area in the engine bay. Just low enough for it to see some wind as the car moves. The end of the pipe is cut at an angle to create a small amount of suction as the car moves along at speed. A small amount of filter media can be gently stuffed into the pipe in a spot that can be serviced at a later date to catch the tiny bit of oil and keep it off the ground.

During my build, I had one local mechanic tell me that I could just run the separator line back into the nipple on the airbox and loop it...
WRONG!!! It pressurized the system and forced oil into the backside of the turbo. Talk about smoke! I had the ultimate James Bond rig until I figured it out. <img src="/forums/images/graemlins/notooth.gif" alt="" />