Adding Subwoofers to a car that has it's main battery in the trunk?

My battery is in the trunk spare tire well.

I'll just say what I said on yahoo (with a few additions) and maybe get a conversation going...

It doesn't matter where in the circuit the battery/alternator/load(amplifier in this case) is located -- The alternator is the source when the car's running -- as it operates at a higher voltage than the battery produces. The battery doesn't unload current until the alternator is maxed out or can't respond quick enough to a sudden change in current demand (which happens a lot with high power sound systems at high volume). Having the battery close to the amps is a good thing since you don't have as much voltage drop in the wire between the battery and amp(s). You may want to determine what size wires your stock lead from the alternator to the battery is and run an extra 8 awg or larger if there's only 8 awg (maybe 6) in place.