Ok so I currently have plans for a box to replace the one that i already have in my truck.

This new box is going to be ported and should look like this.

The sub is a Rockford P3D212 ( http://www.rockfordfosgate.com/products/product_details.asp?item_id=108288&locale=en_US ) and this will be my first vented build. Now it will be much easier for me to put the port on the back of the box like in the picture but from what I understand most people put it on the same face as the sub. I'm just wondering on how much (if at all) the port placement on the back of the box opposed to the top will affect the sound.
It would be work to put the port on top because I plan to mount the console in a permanent down position onto the box kinda like in this picture: (but the box would extend farther back)

 

Back will be fine.