4 12 box design help.

[Spldad82]

I have a 09 hhr im doing a budget build in. Im looking for flat wall or 4th order designs. Im building this for the new generation or people on a budget to show them you can enjoy this hobby without spending a fortune. Im running 4 power acoustik gothic 12s on a taramp 8k. I have super strong electrical that charges up to 15.5 sits at 15.1 at idle. Brand x 275 amp alt with 15.5 regulator on a proto lithium bank. Any designs are greatly appreciated.