Ahh, okay. I don't exactly understand why you don't just install an inverter and use the amp in it's cabinet, that seems like a more flexible solution but I like the idea of customization for the sake of customization... sometimes, you just want something different, which is cool. Try to build your enclosure to match the interior volume of the existing enclosure.

 

Its an extra amp combo that's why I don't mind making it permanent. The box its in now has an open back so not sure if volume of box matters but if I do enclose it should have more punch to it.