Uh ohh...here we go.
I use Mobil 1 Synthetic. I believe it is 75W-90. You will need just over 1 bottle (1.1 or 1.2 I believe is called for by the FSM) so just buy two bottles. A pump makes it easier (though some do it by simply cutting the tip off the bottle on the SDs) and make sure you remove the top FIRST.