For 1000 watt's rms, you can go with Alpine type X's, Eclipse T's, Re x.x.x or the Adire brhama. They are all expencive subs. They are also grate sq, and spl subs!
if you the subs to be atleast 1000w rms a piece, youre most likely going to need a HO alt, which is going to run 200-up, decent amp to power 1 of these subs is around 300-up EACH plus the sub aroung 400-upEACH and you need a HU which is giong to run 100-400 for a decent one.PLus youre going to need box,which is aroun 30 dollars if you build one, and then youre going to need a wiing kit, another 40
so the best thing i would do is 1 15" RE X.X.X dual-450approx -1600w rms OR if your're totally into sq get a idmaxV3 whicll run you about 330 shipped. 1 hifonics 1500d -300 knuconceptz wiring kit-40 sub enclousure-30 with the X.X.X leaves around 100 dollars for a HU(which isnt all that good) but with the Idmax V3 you'll have around 200 dollars for a HU so IMO i think you should either save up a few more dollars, or think about having the 1000w rms each sub and downgrade and have the same amount of output. Remember power isnt everything about car audio.
I meant to say you aren't going to find two good 1000W RMS subs, a quality amp to power them, and a MP3/CD/R-RW head unit for 900 bucks. You're going to have to reconsider your options.