As long as the wheel well liner was still on your car and in decent shape then there's not much of an issue with water getting into the intake. I had basically the same thing on my old 5.0 and never had an issue with it. It's an okay price but I'm pretty sure you can find a cheaper one out there or get a name brand/quality for a couple of dollars more.
but... i bought the exact same mac cai for my car, and even though it works as advertised, the chrome developed some surface rust in several places in a few month's time. the inside surface on both pipes also has a good bit of rust showing. next time I will go with a bbk or something comparable. also with my car, the filter seems to stay alot cleaner where it is located in the fenderwell.
I use a bbk/moroso combo for my car. My filter sits lower and points downward. It would be pretty difficult to get water in there. As long as your wheel well liner is in there I'd say you'll never have a problem unless you like driving through 4 foot deep water on a regular basis!