Leaderboard

For the port size and length you should model the enclosure in a program like winisd that will show you the port air velocity and excursion so you can see how different sizes of port will effect how it all performs. You don't need anything to direct the airflow to the ports except for a flared end piece. Keep the end of the port away from the back wall by at least the diameter of the port. I.E. a 4 inch diameter port should have at least 4 inches clearance at the end of the port.