Well, in diciding how many subs and what kind of subs you are looking for, should u take into play what type of music you listen to. Like for me i mostly listen to hard core screaming, how many sub's fits that style? i like 10" sound, and also since the music is already kind of raspy, should sq be lower on the list of priority?
no. IMO sq should never be let down unl;ess you are competing. i would look into a driver with decent xmax, decent-good SQ, and high output. whats your budget?