Drill a hole,(2 1/2in) and go to home depot, and get some pvc pipe, and shove it in there/bottom it out, and keep bringing it up till you like the sound, mark it,cut it off,bang it flush,seal around with silicone, and shoot some black Rustolium pait on the White pvc.There you go ..prob solved, and dont have to rebuild box,and your subs will get some breathing room, and run cooler, and sound a S H I T load better than what you got going on.Spend another day on that box brother, and port it.You wont regret it.There you are, man Cheap to do, and just takes another day, at the most,and should be happier than what you got going on.Wrong built subwoofer box for the pair of subs in my opinion sorry to say.Good luck to you man.