im not looking to seal off im trying to stay out of wall classes and plan on staying in trunk classesSorry, but after 1k watts I don't use the trunk anymore. You waste too much energy, and you'll be fixing a new rattle every week.
The sub and the port needs to vent directly to the cabin and the cabin needs to be sealed off from the trunk.
I don't know how you're going to do this with a box that has a vent on the side like that.
Sounds like you need a new box.