I am looking into upgrading my home theatre subwoofer. I like what i've heard about the SVS PB12-NSD. But also wanted to look into custom subs. I do not have the necessary tools to make my own box. Is there someone who could make me a custom box or a good pre-fab box I could buy. If I go the custom route I would like to go with a 12" or 15" sub. Do you guys have some recommendations on box, sub, and amp for me. Hopefully keeping the total price under $750?