4 gauge was maximum input not required. either way its better to go with 4 gauge.

Kinda bummed. Got the box/amp/terminal just now but for some reason the sub didn't ship. Wiring should hopefully be coming a little later today or tomorrow.

Guess the sub is coming tomorrow from a second location. Email notification never mentioned anything. After everything is wired what steps should I follow with tuning the amp.

bass eq=0db
level=set it to the pre-amp voltage of your head unit.
x-over=lph
hpf=60hz(stock setting)
lpf=about 80hz. you'll have to estimate this on the dial since it only 30hz and 250hz marked.
mode=stereo.

after you set it to this base line run some music through it. keep in mind this setup won't be really loud but it should be plenty to start with. if it seems too quiet turn up the bass eq some or see if your head unit has subwoofer controls because they may be set low.

Definitely appreciated. Would this be a good enough ground?

i wouldn't share a ground wire with something else.

you can use it and it might be fine though. you'll need to remove the bolt and sand the paint off where it touches the body.

Got it all hooked up. I might need to make a couple more minor tweaks. I'm pretty sure I had to turn the bass eq up close to all the way to get decent bass. Was expecting a little more out of it. But it sounds pretty good. Didn't feel like putting my back seat on afterwards so I'll attempt to clean everything up a bit tomorrow and post pics.

whats the level knob set on?

close to .2 unfortunately i forgot my voltmeter so i couldn't check. But it seemed the best near there. I was gonna check that tomorrow.

just asking because i was going to say you might try adjusting it.