Well, I don't see any mention of an intake manifold on there, so if you're upgrading from stock, I'd look into picking up a complete upper and lower manifold from a '96-early '97 Explorer from the local wrecker, to compliment your heads as a priority before the throttle body. They'll move a lot more air than the stock set up and if you're lucky enough to get one complete, you'll get the 65mm throttle body that comes with it anyway. You'll need to modify the throttle linkage a little, but it's no biggy.
If you don't get a throttle body with it, go with something in the 70-75mm range by one of the more popular brands (BBK, FRPP, Holley, etc}. The only ones I'd really avoid are the overseas brands. Their quality tends to "suck" (no pun intended) in comparison.
