Stereo wizards, i beckon you.

[B 4 You]

alright, i am in the process of making a subwoofer box in my svx. it is going to sit in the spare tire location. i have it all planned out, and it's nearly done. (pix soon) but now i need help with the wiring. my amp will be right next to the woofer, so huge wire won't be necessary because it will be such a short distance. the amp, on the other hand, pumps out 1200 watts. and that's rms. and it needs true 4awg wire. first question, what's the best/easiest/least noticeable place to run that thick wire? i know i'm connecting it to the battery, but where in the car is the best? i really want it to look completely stock. also, i have seen posts about that cell phone connector in the back. could i wire an ignition wire for that? i don't want my amp sucking battery power while the car is off. also, could i simply tap into the rear speakers and put them into the amp for inputs? am i wrong to think that those wires can still be really small, cause they are just inputs? anyways, i'm using my stock head unit, and it sounds amazing, and i want some low end to mix with my piercing tweeters. i want my ears to hurt. (occasionally) is this something that i can do myself, or is it wisest to leave it up to an audio shop? i have a slight knowledge of audio stuff, and i put my speakers in myself and i put new speakers and a head unit into my girlfriends car, but this is a lot of power and i don't want to screw it up. any advice is great. and if anyone knows a good place to buy good, yet cheap power wire, that'd be great. not the wire from the sub to the amp, but the power cord from the battery to the amp. thanks!