Bolt the enclosure to the car and wire from the amp plate to the subwoofer. Wire the subwoofer and bolt it securely into the enclosure. Some subwoofers require a foam seal to prevent leaks, but the Alpine Type Rs have a built-in rubber gasket so no foam is required. Grind down the surface to smooth out any imperfections. Duraglas and Rage Gold body fillers can be used to further smooth the surface. Since this enclosure would be finished with matching trunk carpet (which hides many surface imperfections), there was no need for the additional finishing steps in this case. Spray glue on the enclosure and be sure to coat the back edges so that the carpet can be wrapped around the back of the box. Allow 10 minutes (or until the glue is no longer wet to the touch) for the glue to set before attaching the carpet.
When it's all put together, the huge 15" subwoofer tucks neatly into the corner of the trunk and takes up hardly any space. Most importantly it hammers out loud, low bass from the owner's favorite Sirius Satellite Radio channels, mostly old-school rap and heavy house beats.