Below is a quick link to a video I just posted to my channel. Anyone that is suffering from a bad PVC/CCV may want to consider cleaning their intake valves with this method or Walnut Blasting. As you can see from this video, I had quite a bit of carbon build up on my N55. Not sure how long the previous owner went with the this Bad PCV system. Also, toward the end of the video I have a quick review of the non-OEM valve cover I picked up on Ebay. It was really good quality.
N55 Intake Valve Cleaning and Replacement Valve Cover