There are a couple of different CAI concepts out there; the ones that replace the airbox with a larger airbox and a much larger filter, and those that replace the airbox with open element air filters. The first will give you very subtle improvements, slightly better throttle response since the airbox is larger in volume the OE, and, the filter is much larger (even if you go with the dry style elements) and can flow more air with less intake/filter restriction and last longer before needing to be cleaned as a result. The OE airbox and these aftermarket styles that replace the OE airbox with an aftermarket one utilize the stock routing that brings cold air from in front of the radiator routed under the front of the hood on top of the radiator core support.
The open element style increase noise and depending on the brand, they can actually bring in more dirt if they pull from the inner fender well when off road, or pull from the engine bay as a result of poor or no air routing from a cold source.
I actually ran numbers comparing the size of the OE filter and it restricts up to 9.4 Hp as you near redline at WOT...one thing to keep in mind, the Raptor uses the same OE filter that the non-HO ecoboost in a regular F-150...so an engine that makes another 80 Hp and like 120 ft-lbs of torque doesn't need more air?---it uses more fuel, so it must need more air, right?