Alpine SWR-10D4 Type-R 10" Subwoofer with Dual 4-ohm Voice Coils
This thing is awesome.  I have it hooked up to a Kenwood KAC 7205 1000 watt amp and WOW!  Im sure glade i got a sub now because im never going back.  Some pictures at the top were uploaded by me.  Best part is i got the sub and amp free from a friend!  LOL.  But seriously this thing is worth the money.  Make sure you guys have some left over for a sealed enclosure or port hole box.  Mine is in a sealed box.  I can get this thing to shake not only my trunk license plate but also my rear view mirror, door mir