IM FINALLY GETTING READY TO ADD SOME SUBS INTO MY CAR TO COMPLETE MY SYSTEM. (SO FAR I HAVE POLK AUDIO DB651 DOOR SPEAKERS RUNNING OFF AN APLINE F300 4 CHANNEL AMP) I HAVE DECIDED THAT SINCE I'M A FULL TIME COLLEGE STUDENT AND WORK FULL TIME, BUYING A SUB ALREADY BUILT INTO A FACTOR ENCLOSURE...