JBL amps suck ALOT of power. If your looking for something cheap and effective, get a Lanzar 2 channel. They are stable @ 2 channel 2 ohms, and 4 ohm bridged to push about 1000watts RMS. My buddy has a Lanzar 258 on two 12 inch sony explodes. It doesnt cut out and it hits hard on lowpass. He has it running with one channel to each sub and its pushing 400 watts RMS and 800 max. He payed like $220 CDN for it. Its a two channel 1600 watts max (bridged at 4 ohms)
Its fused with two 25 amp fuses in series plus a 50 amp on the battery and he hasn't blown a fuse yet, so it can't draw more then 50 amps.
You may also want to check out www.ikesound.com
if you have a credit card. They have incredible prices, but the only thing is they don't come with factory warranty. Their products are warranted through ikesound for 1 year. You can get an Alpine MRD-M605 (400 RMS @ 2, 250RMS @ 4 and 900 MAX @ 2 *** note these are 12V figures) for $230 regular $450. This amp is also capable of 600 watts RMS @ 2 ohms running at 14.4V
I hope this info helps you a bit.