I have driven through many rain storms this past winter. I didn't experience any problems what so ever. You just need to drive carefully. If I had to drive through a puddle, I went through it at like 1-2 mph's with the motor idling. If you have to go through a puddle, make the motor idle so it isn't sucking for large amounts of air. Some guys actually speed up so that their tires break the water and make the motor idle at the same time.
You will only experience "hydrolock" when the ENTIRE filter is submerged in water. A few splashs will not hurt the filter or your motor. In fact, I heard that a LITTLE moisture is actually good for the filter and your motor because it rises away some dirt and dust. I don't know if that's true or not.