i drove from portland to seattle (4.5 hours) in poaring rain, and was fine, and i dont think it gets any worse than that, so yea like already stated, just dont drive in big puddles. and if you want to be real carful you can buy and injen watershield for the filter, ive got one
As Isaac (I think it was him) once said, picture your Intake
as a straw, and walk into the rain and see how much rain from the sky you can suck up. Little or nothing, right? The straw or Intake
has to be submerged in water in order for it to suck any water into your Intake
As for big puddles, as long as they aren't as tall as your car, you will be fine.