ok well first off bff larry is right, go ahead and get 1 awg wire for this
Make sure your head unit, whatever it may be, has at least two pre amp out puts that way when you add another amp, you dont have to buy a new deck
Get a good brand of amp, i recomend a kicker amp cuz ima recomend a kicker sub(due to quality for price)
A kicker zx 400 amp, it will prolly run over on rms, my 400 was like 540
A kicker cvr 12 in a really big prefab ported box, prolly tuned under 40 atleast( order on ebay)
Then thats it for now, just hit me up when you go to an amp for the speakers and speaker upgrade. But this will be a great start. Let me warn you though! your always gonna want something louder hahahaha