need assistance choosing a sub amp

Yes less voltage will make less power.  For example a 40 amp draw at 14.4 volts will make 576 watts as long as the system is 100 percent efficient.   That same 40 amps at 13.8 will make 552 watts as long as the system is 100 percent efficient.Garbage in EQUALS Garbage out...

so theoretically i could use a amp rated for a higher wattrms then my subs? subs rated at 600wrms@2ohm opinions on these? http://www.woofersetc.com/p6859/FD-6001--ARC-Audio-1-Channel-620-Watt-Amplifier.htm http://www.woofersetc.com/p7766/RUB1700--Soundstream-Monoblock-700-Watt-RMS-Rubicon-Series-Subwoofer-Amplifier.htm http://www.woofersetc.com/p7845/DSC15001D--MB-Quart-Monoblock-1500-Watt-Discus-Series-Class-D-Amplifier.htm

I say yes to the ARC audio, the rest on that list are ok.Garbage in EQUALS Garbage out...