I've run a modified March Ram air kit in my 89 Mustang since the late 90's, with over 150,000 miles since then, routinely in the rain and snow, without any issues. I cut a 4" by 6" hole in my bumper cover about where the fog light goes in a GT on the passenger side, which does raise the intake point some, probably 4-5 inches center to center. I also added a screen on the front to keep out the leaves and such. I replaced the cheapie dryer vent hose with a custom built fiberglass pipe. It's been a great mod, and is still on the car, now with a 369 under the hood. Water has to go vertically up roughly 18" to get to the air box, and it's not like you're going to do 6000 rpm and such when it's raining....