Is the intake the only modification you're going to make?

Reason I ask is that the baffling on the stock intake is actually not restrictive, it's just a noise cancelling agent. The flow of the stock intake is actually very well matched to the 5.4L's performance, and the aftermarket intake will likely only give you gains, if any at all, above 5k RPM.
The aftermarket offerings are commonly referred to as "engine bling" for a reason...they provide little to no performance improvement over stock, but they might look better. Secondly the aftermarket intakes usually pull air from the engine bay, whereas the stock intake pulls from the fender well, which should be cooler air.
Honestly, you'd be better off going with a hand held tuner/programmer with custom tunes, as you're likely to see both performance gains and possibly economy gains depending on your driving style.

EDIT:
Here's a similar thread from just a few days ago...was right on the first page of the forum:
https://www.ford-trucks.com/forums/1...-worth-it.html