Check out TC Sounds. The TC1000's, the first line they have, are rated for 400wrms but can handle 1000. Stay away from RF. Good Luck!
Unless you have very expensive woofers, this might not be economical. Large speakers are expensive to recone, probably $100 or more each. Here are a couple of places to look:
try looking at www.crutchfield.com They give the dimensions of their stuff. You can find something that will work.They carry 8" subs even a Rockford Fosgate P1S48(Punch Stage 1 8" 4-ohm subwoofer) should plug into your system If you send for their fr...