go to lowes or home depot and get some bolts nuts and washers, one for every wire you need to run through the box. drill a hole the size of the bolt and put the bolt through with a washer on the outside and inside of the box. start tightening the bolt, when theres only a small gap left, hook the wire going to your sub on the part of the bolt inside the box. now hook the wire going to your amp on the part of the bolt outside the box. now tighten down so the wire is held tight against the box by the washers. now your good to go, everything is still sealed tight where it needs to be and no ugly holes in the box(you can do it on the side and no one will even see it)