sub/amp purchase

Just looking for a little advice since everyone on this forum seems to know their doodie. I have been reading the forums a lot lately just about wiring and other stuff and am very impressed, and just in awe with all the knowledge. I am a college student on a very tight budget, but am looking for a set of possible 2 10"s(but really any size is good, I have just heard 10's are very tight bass) and a amp. I am very open to suggestions. The car is a '73 Plymouth Gold Duster all stock. Budget: 400 Type of music: Hardcore, Metal, Punk Style: I want the tightest bass possible but with the budget in view. Space: I have a entire trunk to work with so space means nothing. Current Speakers: 2 4" Alpines and my deck in a custom console box on my tranny hump. A set of 6x9 Infinity Reference my bro got me for christmas, and a 400 watt swapmeet amp powering those 4 speakers. I also have 2 10's currently in the trunk that are Visonik, a old pair that my bro had in his truck that just don't hit to my liking. Current subs or amps I am looking at: Eclipse 10" SW6000 JL 10" 103v2 Alpine M650 or M850 amp Any advice is great advice. Thanks in advance, ~Steve

Thanks for the fast response. You used the word fs which after looking at the forums and doing a few searches still makes no sense(sorry I am still learning about all this stuff). Also if I am able to get 2 12"s but the power would be a little bit under RMS, is it worth it rather than to say put 2 10"s over rms by about 50 watts?(keeping my budget in mind, this is my dilemma) Also if anyone else has heard some systems blasting metal/metalcore(lots of stuff with double bass on the drums) I would like to hear about it. Thanks again! ~Steve