Thanks for the info, and the impeccable links. I have to say, the P-3's seem horribly expensive for clapped out old hardware; your link 3 mentions that the P-3's are already decommissioned, and being pulled out of the Arizona boneyard. Yet the purchase price is 100 million, and another 50 million to get them refurbished and ready for service. For four units, that's some 37-38 million USD each. OUCH!
And this leaves Argentina at the mercy of an increasingly-fickle US for spare parts. Somebody here sneezes, Argentina get slapped with sanctions, and those aircraft are grounded. Regardless of your politics, you must admit that Congress has gone crazy overboard with the whole sanctions thing in the last decade.
It just seems to me that the same 150 million, or even half that much, would buy much more bang-for-the-buck from Embraer. And with the source of spare parts being right next door, and a fellow member of Mercosur. Not to mention that Brazil is far less sanctions-crazy.