How do I mount the sub to the box? Ok, yeah I know I drill holes and screw it in, but do I have to put anything on the back of the mounting frame? Like some kind of seal to keep air from leaking out? Or am I suppose to just screw it on and call it a day? I know air leaks are bad so I'm just trying to avoid a mistake. Any particular type of screws I should use or just whatever fits? Thanks.