Infinity Reference 1230w 12" 4-ohm subwoofer at Crutchfield
Infinity Primus 3000A 300W RMS Power Compact Mono Subwoofer Car Amplifier System Bundle with 12" 1200W Max Power High-Performance Car Audio Subwoofer and Amplifier Wiring Kit - Road Entertainment
Best Buy: Infinity Reference 12" Single-Voice-Coil 4-Ohm Subwoofer 1260W