Pioneer TS-A300D4 12" 500W RMS Dual 4-Ohm A Series Subwoofer
Alpine S-W12D4 12" Dual 4ohm Subwoofer with GTX-500 500 watt Mono Amplifier and 100% Copper Wiring Kit - Creative Audio
Amazon.com: 8 Inch Car PA Woofer - 500 Watt High Powered Car Audio Sound Component Speaker System w/ 1.5" Kapton Voice Coil, 55-6 kHz Frequency, 89.2 dB, 8 Ohm, 40 oz Magnet - PylePro PPA8 , Black : Electronics