Im doing this on a 94 accord lx sedan, with an alpine 3de-7886 head unit. The headunit doesn't have any subouts or anything like that. It has 1 preamp and thats about it. As for being new to this kind of stuff, i guess i am and im not. Ive already installed some catz msx lights myself which required running wire through the firewall to the battery. Wasn't hard, just took a while. I also just finished installing my components about a month ago which required me to take off panels and such. The only thing i really need advice on is how to the the wires from the firewall to the trunk. I can handle the rest easily.

So basically what you are saying is that really im going to only be running the power wire through the car (i can ground somewhere close), and i splice into the the rear speaker wires for sub input?

And if i ever did get a new head unit with rca subout, i would have to run those through to the trunk from the head unit right?

Is it worth changing from high level to low level inputs if i ever do replace my head unit?