like has been mentioned...i'd get a H/O alternator, and definitely upgrade the battery under the hood. as big as you can. perhaps add a second battery.
x2. those speakers are rated at 2000 watts RMS, and if you dont know what you're doing, i'd be careful about putting 3kw to it. it can handle it, yes, but be careful. i'd build the box on the smaller side of things if you're going to give it more power.
the xplod will explode
ahem...sry
http://www.stevemeadedesigns.com/board/ind...showtopic=13280
that link will show you how. basically the big 3 helps better supply your car/system with power
x2. it'll be pricey having to get everything (batteries, alternator, possibly multiple runs of 1/0), but it takes power to make power. and power = $$$. just take your time and do it right and you'll be happy in the end