Dependent on which voice coil configuration CVRs you have you'll want between 600 and 800w total to spread across the two at whatever impedence you need the power at.
That level of wattage for under $300 should be very easy to source. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif