That deck needs to be wired directly to the battery or another point where extra amperage is available. Alpine uses a heavier gauge wire on their high power decks because to create more power, the deck draws more power... and not nessecarily volts, but amps. That deck draws a good 15 amps at bass peaks... thats too much for the tiny stock 20 gauge wire. If you play your music quietly, then the stock wire MAY BE adequate... but I still dont recomend it, as you will still be starving the deck amp of power.

Re-wire it right... the manual stresses how to wire if for a good reason. Be sure your ground is good as well... ground to the frame of the car, not the harness.