Much more than they need. You can get those subs loud in a ported box, but if you are looking for SQ, sealed is the only way to go.
If you check an excursion plot, it only takes about 120W each to get the 10 to Xmax in a .65 cf box.
I had a 2100HCCA on 6 of them wired up for 2 ohms. I got all they had to give with that amount of power.