the deal is fair however with that amp you want dual 2 ohm subs in order to give a final two ohm load to the amp to get full potential out of it.
they are selling dual 4 ohm that will give you a final load of 4 ohm or 1 ohm both of which are not right for that amp.
if these are single voice coil (which i thought they were) forget everything i just said lol
it says dual though so be sure to double check