adding amp, sub to stock system

I own a 2007 Toyota Camry LE with the stock radio(NON JBL/ NO AMP). I have no power antenna cause it's built into the rear glass. He's the deal, I have existing audio gear from my last vehicle(96 GMC Jimmy) and now getting around to installing it into my car. I wont go into detail about the branding of my gear as I don't want to be flogged and beaten!! I have 8 ga power to run from Bat to 600 amp. Is 8 ga sufficient for the amount of wattage?

Amp details:
4 x 75 Watts RMS at 4 Ohms 4 x 150 Watts Max at 4 Ohms
2 x 300 Watts Max at 4 Ohms Bridged 4 x 125 Watts at 2 Ohms RMS
MOSFET Automatically Switches to Maintain Rated Power Over a Wide Range of Battery Voltages
Stiffly Regulated PWM-Type Power Supplies
Variable Input Level Controls for Each Pair of Cannels
Variable High & Low Pass Crossover Controls
High-Efficiency, Heavy Aluminum Heatsink
Remote Subwoofer Bass Control
Electronic Crossover Network
Line Outs for 1/2 & 3/4 Channels
Bass Boost Circuit
Bridgeable at 4 Ohms
2 Ohm Stereo Stable
Tri-Mode Capable

I already have my 10" 4ohm DVC sub (which is wired in parallel I think) installed in a sealed enclosure. I also have a scosche LOC that I will use on my rear speakers to send the signal to the amp.

OK, my question is where to hook up the remote turn on lead. One person already suggested the accessory wire, where would I find this? Other than that, I got the rest covered I think. I just gotta drill a hole in the firewall and add a grommet for my power wire.

Thanks
overkil

8 gauge would be sufficient but hardly "ovrkil".  Pull your subs and make a diagram of their wiring.  You have to be sure of this stuff.  And connect the remote lead to a switched 12 volt source.  You'll know it's switched when you don't get any voltage measurement (use a digital multimeter...easy to find) when the ignition is off.  With the key to ON or ACC, you'll read 12 volts.  Sometimes you can find a wire close to your amp location.  I found one in the trunk of my Taurus about 2 feet away from the amp, but usually you'll more readily find one under the dash.  Just probe some connections.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

if your sub is parallel it will be 2 ohms mono. Too low for amp unless it is a high end amp that can handle the impedance load.

you really dont even have to drill a hole in the firewall and it might be better that you did not so you dont have to worry with any other problems if hit something you shouldnt. You should be able to locate a place in the firewall already where wires come through and just try to run you power wire through that. I have seen people using stock radio get the remote wire from the fuse box, as in the radio fuse in the box that only works with the ignition on. If this is a good method I have no idea since I usually have after market radio's to get the remote wire from.

I have heard of remote creators. It uses the audio signal from an output on radio to switch a relay to power a remote wire to amp. I would check the back of the radio for a wire that when you turn the radio on or off it will show 12v and 0v respectively. Then if all else fails tap into an ignition switched source, ex. ignition wires, at fuse panel, or try looking up remote creator. click link Peripheral lvt2

LVT2 cheaper cost

Ok....I have everything installed now. Came out pretty damn good I must admit, looks anyway not performance yet.

What would be the best way to power this sub? I have the LOC setup for 2 channels (1&2) tapping off the rear speakers. Should the sub be wired for parallel and then bridge the channels to power the sub?

If it's really necessary to know the brands, then the amp is a Lanzar Viberant VIBE 415 4ch amp with the above specs and the sub is a Volfenhag 10" DVC 800W. Here's a link for the sub details...I bought these dirt cheap 5 yrs ago, I gotta do something even if it's wrong!!

https://www.volfenhagaudio.com/subwoofer_hp.html

Thanks for any help