sub opinions?

hay, im stoked to "be a part" of the 12 volt!! now down to the dirty!  i would like some input on some subs i am looking at. i would like a good mix of sq and spl.  my ride is an '04 sebring. the system i have now is

h/u alpine cda-9855

memphis 16eq p7 parametric eq in the glove box

1/0 all the way back

x-static battcap (300 ?)

sub amp hifonics bxi 2610d

amp 4 mids and his hifonics zxi 8408

subs audiobahn aw1506t 15''s

the subs are in a lexan sealed box with 2.2cuft for each sub

front stage mb quart rsi 216

mb quart 6x9s out back

yellow top with 120amp stock alt. have not done the big 3 yet but i will.

i know this is NOT a "good" set up. its not like i payed a lot for it er nothing like that.i know the amps are over rated. i would like to think that bxi 2600d is putting out 1800-2000 maybe?i know that not a lot of ppl on here like hifonics and thats cool. i did not know mb quart was no longer the mb quart i remember.

but this is just to get me by for now. i had an all audiobahn system and i so wasted my coin!! its all teash!! so once i get some good subs i will upgrade the amps and replace the mb quarts with bostons.

for subs im looking @2 fi bls loaded or the q's, mtx 9500, memphis mojos, fosgate t2s or some re audios all 15". are these all spl sub im looking @?

i should be able to give them about 3-4cuft for each sub. ported and tunrd to 33hz er so. is there some other subs i need to check out?! let me know. any thing i get will be better than them audiobahns. thay do hit o.k. for the $134. i payed for em tho.

 thank you for your time!!