Upgrading/ custom box

[shooter18]

Hey guys,

im upgrading my stereo adding

-Pwh304 MB quart 12" sub
-Rockford Power Series T400-2 Channel amp for sub
-Rockford power series T600-4 CHannel for rear and front speakers.

I will be making a custom sub box for a vs Berlina and still unshore of how im going to set it up, if anyone has any pics of custom jobs they have done themselves or had done for inpiration that would be great.

The MB Quart site saiz the box size for a sealed enclosure is from .5 to 1.3 Cubic liters what size box should i make it (i listen to all genres of music).
I currently have a 4 guage power supply i was going to split the wire with a distrabution block will that be enough to run the two amps which both require 4 guage.

Any help is much appreciated,