With the intake, you're basically buying the sound. Near redline, you might get a few more hp, but you won't notice it, or you will, but it's mostly placebo. Is it worth it? It depends if you like the intake sound. I know I'd be all over an intake made for the 2.5..
The drop in will save you from having to buy paper filters when they need replacing. Just be careful to not over-oil, and clean the MAF sensor every so often to make sure your engine is getting the right a/f ratio. (I do this regardless if I have the paper or oiled filter.)
Last, I just want to add that paper filters will provide the best filtration. The oem intake provides good, cool air. If you were going to go K&N, I'd get the typhoon.