I would go with 2 12" IDMAX subs. They are 330 a piece. That is 660. You then have about 340 left for an amp. I'd recommend a Hifonics BX 2200D. That is 489 but well worth the price. With this set up which cost just over $1000, you will have great sq and spl probably at least in the low 140s.
If i had 1000 dollars to spend right now i would go with 2 diamond cm3 12'' subs. You may have never heard of them because they are sold only at a authorized dealer. No internet sales of them either. 2 12'' subs in a hooker box will be as loud asanyhting you could possibly stand. Try these!! 3 year warranty, if u blow it you bring it where you got it, they hand you a new one
or......u could always go with a 15'' triple X from re [sorry that's my favorite out of all i've heard mentioned].