Heres my rig:
JVC KDG 230 http://www.jvc.ca/en/consumer/product-detail.asp?model=KD-G230
2 x 12" MMats Procast 600 WRMS Dual 4 ohm vc in a custom 4.5 cu ft. box, port tuned to 38 or 39 hz
1 Memphis PRD 1000.1 running at 1 ohm (Subs are wired in parallel)
1 Sony XM255EX powering two panasonic 160 WRMS each ex-house speakers.
and the two front door speakers 4x7 AC Delco paper cones.
Now, I just upgraded the Amplifier, I was running the subs off 360 WRMS combined. I thought that jumping up to 1000 watts RMS would make a huge difference, but it just aint cutting it for me. I have seen vids of people running this amp, and two 10's, and they can barely keep their car doors from popping off the car. Why is it that with my head unit at 30 vol. (Max is 50 I think) The bass won't even make my remote dance on the roof.

Gains on the PRD are 1/3 or better, 0db bass boost, subsonic is at 35hz, LP filter is at 60 Hz.