The key thing you need on that cold-air intake is the water-bypass. Basically, if your main filter end of the intake gets submerged (if it gets set low instead the top of the engine compartment), or if somehow it gets completely soaked, the intake system will draw air in through this foam bypass on the intake line. Here'a a link to a pic of what I'm talking about.
http://www.modernperformance.com/dcx/aem_bypass.shtml Hope that helps.
Note that if you are installing a cold-air intake system and your intake is going to be at the top of your engine compartment, then you aren't going to get any better than that without getting a snorkel. You'll only have a problem with your intake if you get completely submerged. The occassional splash of water up onto your engine is not an issue.
