heavy rain + CAI = hydrolock.
short rams don't have this issue (unless you're driving in 3 feet of water, which means you've got other problems)
the CAI pulls air from behind the fender, the filter is at the same height as your brake rotor. the waterproofing in this part of the car is not as tight as it is in the engine bay, where a Short Ram would mount.
the CAI bypass valves are supposedly worthless b/c they defeat any gains made on the CAI.
the Short ram won't help as much because the air you're pulling is hotter.