well, I have tried to think about this, but I'm not sure how practical this would be, with such limited space, but in the pipe, if you run one, put an AEM bypass valve there, but again, I'm not sure this is a good idea
Goto a suburu dealer and check out their cars. I looked under the hood of one but I forgot how they prevented water from entering.
Another option is to run a pipe from the stock fog location up to the airbox. PT did this so ask him.