http://www.edesignaudio.com/product_info.php?cPath=1_22&products_id=47 will do more than rated power at higher voltage.
Doesn't look like it would be enough kick. Need a mono block, then split. I'm running 14.4 volts usual. IDk but it looks like it would power one of my subs.
it would put out 800watts or so with a good electrical...cheaper than a 500/1 and I think that 250/sub<400/sub. since the ohm load of your subs wired down is 4ohms. it is fused with 3x30amp fuses. I think it would get the job done and cant beat that 5 year warranty.