What you have to remember about air flow modifications (which makes up a large portion of modifications in general) is that they all compliment each other.

Getting a good intake such as an AEM CAI or V2 will only give you a few hp difference in comparison to lesser intakes, but if you continue to modify, say with other bolt ons, the higher quality intake will also increase the power you gain from the header, exhaust system, valvetrain, intake manifold, etc etc.

Do some research on the intakes and see what impartial (as much as possible) sources have to say about them. Advertisements and the company that produces them will always make them sound like the best out there.