Install Guidance

Well i was just lucky enough today to have my brother in law give me 2 12" pioneers in a box w/amp already hooked up for free. Now im gunna have to install them and just want to run by you guys what i believe i'll need and if you can tell if im missing anything or not.

First the specs that i know of on the stuff:
will be buying a Pioneer 4700MP tomorrow
2 12" pioneers (no clue on model, i have pics) 400W each
1 550W (275x2) Soundstream SL552 amp

http://img.photobucket.com/albums/v75/Dusstbuster/Picture_2407.jpg
http://img.photobucket.com/albums/v75/Dusstbuster/Picture_2406.jpg

So here is what im thinking im going to have to do, correct me if anything else is needed or if im doing extra things that i dont need.
First ill need to get some 4ga wire to connect the amp to the battery and some RCA cables to connect the headunit to the amp

Ill also need the sosoche(sp) wiring harness to connect the 4700 to the stock wiring.

Install head unit and do all splicing/soldering needed with the harness,
Connect the amp to the headunit, done?


Any further descriptions of the install would be nice too, ill also be checking out installdr as well. Thanks!

EDIT: also, which harness would i need from all of these?
http://www.scosche.com/scosche_caraudio.aspx?CategoryID=78

ill just copy and paste what i posted in my local forums:

god help me this is a pain in the ass
http://img.photobucket.com/albums/v75/Dusstbuster/Picture_2422.jpg
http://img.photobucket.com/albums/v75/Dusstbuster/Picture_2421.jpg
http://img.photobucket.com/albums/v75/Dusstbuster/Picture_2420.jpg
http://img.photobucket.com/albums/v75/Dusstbuster/Picture_2419.jpg

(In 2420) the 2 that i can connect are the black one and the grey/red one on the right
side in my hand, those 2 connect to (in 2422) the one on the right that is grey and red and the black/metal plug on the left, the one that DOESNT have the T on it, NOTHING else fits.

This is seriously pissing me off. The amp either doesnt have a power light or isnt turning on and NONE of the speakers work, the radio doesnt even play music. The only other thing i can think of is that in (2421) there are a grey and black connector inside the console on the right side that are on the metal......the installdr article talks about them it seems like but ive never had to deal with them so im not sure. ANY help is awesome. And as of right now i still refuse to pay for professional help, im not gunna cop out this soon.