Ive wanted to do this forever. But I keep cycling thru the amps in my car, none ever make it to my room LOL!
Ill be honest though. To do the power he says (900wrms), he has LESS Then half the amps required to do it. Voltage drops are not normal like he says, and they can hurt an amplifier, and most usually amps do rated power at 14.4v because that is what the charging system in your car puts out at the alternator and thats what these amps are mad for. You dont get the RMS wattage at 12.7v unless it states so.
For 1000rms watts contentious you need about 60 amps. Like my amp in my car, I need like 72 amps because its a 1300wrms amp. I personally wouldnt think about using any high end stuff with any cheapo supply like he says. Use nice things so you dont burn down your house when either or fail.