Rockford Fosgate T212D4 Power Stage 2 12" subwoofer with dual 4-ohm voice coils
Two 1000W quality amps (like soundstream) the right size box and follow the directions to bring it down to 1 ohm. It will bother your neighbors! But it will please you with clean, soul shaking bass. Throw in the right seperates and you'll have an impressive system. Better get a car alarm and bolt the box down then weld the bolts!