The amp makes a HUUUUUGE difference.
If you want loud noise, then by all means go with a shitty amp, and 2 MTX 15's...
If you want accurate, clean, bass, get somthing thats rated ONLY in RMS power, has a dampening factor of at least 200, DOESN'T have pointless flashy junk on it like neon lights, or excessive crome...
A decent 12" like an Orion HCCA, Fosgate RFD series, JBL GTO, Cerwin-Vega Stroker, or JL W6, will all hit hard as hell and clean when powered by a good 200watt ish amp.
If you find that the one 12 isnt enough you can always add another, but DONT SKIMP ON THE AMP!
Also... I have personaly felt that while subs in bandbass boxes can put out an insane ammount of SPL, they usualy sound very "One-note" meaning, all the bass sounds exactly the same..
If your looking for deeeeeeeeeep bass go with a sealed enclosure, if you want "thump"
do a ported box. Make sure it falls within the correct parameters. Just because a box has the right size hole cut in it, doesnt mean its the right box.
[ August 20, 2001: Message edited by: Wildcat ]