i had to trade intakes with my friend. I used to have a Injen SRI, but my friend had no fender liner anywhere and he was scared about the same thing you are so we traded SRI for CAI...
Now obviously there's a easier option than that, but honestly I dont think there is a water shield for injen or even aem.. aem just has the bypass valve, but honestly its not needed. back when we had TS gaston and flooded out richmond I rode home through like.. 5" of water and I'm lowered and had a CAI. no problems at all bro. Just use extra caution around deep puddles. The only way it's gonna affect you is if you submerge the filter