i would say that after box rise you will be right around one ohm so just wire to .5 ohms and use a dmm to check the impedence after everythings all wired in the box and see what you get.
what are some of the good 2 ohm stable amps that will put out 1500-2000 RMS? I am looking at the Kicker zx1500.1 right now. I have about 500 bucks to play with for an amp.