I bought the same sub you have, perfect 12.1dvc, for my girlfriend, and got a 600watt amp for it. the brand sucks, and I almost tried it as a joke, just because I thought it would sound like crap. it didn't, and it sounds fantastic. Its been awhile since i've done anything with car audio, so I dont want to tell you anything and have you end up ruining a high quality sub like that, so here are some sites i used to learn what i needed to do:
http://www.transcendentsound.com/amp..._impedance.htm
http://www.electronixwarehouse.com/e.../whatsdual.htm
http://www.a1bigaudio.com/speakerimpedance.htm
by the way, how much did you pay for that sub? please tell me you didnt buy it retail...