I've heard a couple guys with Injen intakes say they whistle at idle and drives them crazy. I have an AEM like the cat above with pics and I've not had any problems at all with mine and I like it very much. I noticed a little bit better throttle response and honestly, I like the sound of an air intake vs stock airbox with a K&N drop in filter. But I figure you might gain 1-2hp from it, not much. And I've driven through rain and snow with my intake for 2 years now without any problems, so with this particular AEM setup I wouldn't worry too much about water being sucked into the intake. However, I did have an AEM cold air intake on my Civic and it pulled water into the motor when it was raining really badly and I accidently ran through a deep puddle. Forunately I was able to suck the water out of the intake mani and head, changed the spark plugs and she fired right up and ran fine. But if you're worried about hydrolock, buy a AEM bypass valve for $40. SCC magazine did a review a few years back with a NSX and they completely submerged the intake pipe in water and the bypass valve worked flawlessly.