You would want to go with 2 12's. But flip flop the boxes. Go with sealed insted of ported. Does your choice HAVE to be P1's. If i was you i would look into other RF product. You would be better off with Punch HE, or the T series or even P3. Personally i dont like the P1 and 2's. There too weak, there like RF Punch Z's. For rap you will want something big, but not overkill.
Im very familiar with EBAY. I do not like EBAY because of the shipping cost, the fact that its sort of used, and that it takes a long time to get to me. I live in alaska so shipping stuff is not always the best idea. Otherwise I would use EBAY. Since im not, im getting all my stuff localy