i have the rockford fosgate 500a2 amp (250x2 @ 2 ohms) with 2 12" RF he2 subs, they take 400 rms and 800 max but i only run 250 each from the amp and it is LOUD. be sure to get a SEALED box for the best sound quality. a sealed box will make the bass notes more percise and pinching, instead of a bandpass box which will produce a little more sloppy (but slightly louder) bass. i used to have a bandpass and i ditched it for a custom sealed, and i am happy. i paired it up with the original kenwood mp3 cd player and its been doing its job for almost 2 years, VERY nicely. i am constantly commented on my system and i would recomend it to anyone. cost... im not sure about current prices. check www.ikesound.com .. he always has real good deals going on. good luck.