Amazon.com: Alphasonik AS8DF 8 inch 600 Watts 4-Ohm Down Fire Shallow Mount Flat Enclosed Sub woofer for Tight Spaces in Cars and Trucks, Slim Thin Loaded Subwoofer Air Tight Sealed Bass Enclosure :
Amazon.com: Pioneer TS-SW2002D2 8-inch Shallow-Mount Subwoofer with 600 Watts Max Power : Electronics
Amazon.com: Kenwood EXcelon KFC-XW800F 600W Peak (150W RMS) 8" EXcelon Series Shallow-Mount Single 4 Ohm Slim Subwoofer : Electronics