Fair enough but im sure you can make it a lot better.and why is it lulz at my attempt to make it sound good. In technical terms it would be far from "proper sq" but the way I like my music, this will be the closest to ideal as I can imagine.
For starter PLEASE get a new box. Let Buck design you one. They really aren't hard to make and can be made for less than 60 bucks in supplies. You have to know someone with tools? If i remember right your current box is tuned to ~55? Its hardly a sub at this point. Bring that down into the 30's, 35 is always good for most people. Remember subs play low notes. Cross these over at the same as your front speakers.
Set your gains better too! Use the dmm method(google it/search for it). "gain set at around 6/10 and h/u at +3/6" Im not sure if that is bass boost or an actual control for the bass that is +3/6 but with 4 volt preouts you are most likely clipping your subs. The dmm method will give you your theoretical power output but should be good enough.
Im a little confuse of what all is running up front? What are your crossover points?
BTW good job on your electrical, you will have an electrical system better than most running 2k plus around here. Your install skillz are actually pretty good too.