I have two Polk Audio 12's in a Q-Logic Banpass box. I'm running 400 watts to each sub. A word of advice, (I work for car stereo at Circuit City) cut out the ski hole but point the subs away from it. That will give you the best bass. Also, as far as sealed vs. bandpass, it depends on what subs you are using. Certain subs sound better in bandpass others sound better in sealed. Let me know if I can help anymore