Yeah the Atlas 12 or 15 whould be better for the price. They only need around 200rms and will blow the eclipse out the water. For the price there is no comparison. If you do go with the Atlas subwoofer i whould go ported. You wont believe how loud it will get and how much sq at the same time. Check it out if you dotn believe me. www.ascendantaudio.com
p.s. You will only need one subwoofer if you go with the Atlas 15.
Also, check out indoaudio.com I saw two dual 4ohm VC Memphis M3 12's for a total price of $310.00 plus shipping and handling. My cousin has two in a S-10 extended cab and hit 151.6dB's with a memphis 1100D amp.
2 atlas 15's whould hurt..lol With one 15 ported you can hit about 140db if you run it with a solid amp. Not sure how much harder youll hit with another one but if your into that it will be loud. Trust me. If you really wanna know for sure go ahead and talk to chad the owner of www.ascendantaudio.com and he is a super cool guy. Call the order # on the website and ask for him. He is so kind with answering your questions. Give it shot. Its your best bet for the price.