I have a question about the ports.

1- I am building the 2Pi towers. Will it make much difference if I use a 4 1/4" inch hole instead of the called for 4 1/2.

How long is the port. I know that you say that the port is the thickness of the wood. Does this mean that a tube is not required inside the box... just a hole? I am using 3/4" plywood stock, thanks again Wayne.