A cai is lower to the ground so you will take a greater chance of dirt and water geting into your engine. Ever hear of hydrolock? I have also heard that you can get more torque from a shorty.

 

As long as you are moving, hot engine bay temps shouldn't be that bad of a problem. Once you start replacing converters with up/down pipes and midpipes, you'll be getting ride of a lot of that heat. If you're getting offroad in your WRX, go with a short ram. The cold intakes get air from down near the ground. You can get the AEM with air bypass valve, but you shouldn't have to depend on that just to drive the car. Even in just rain, the ram filter will stay cleaner longer. Also think about the length of the intake pipe before it connects to the compressor inlet on the turbo. The longer it is, the more vaccum there will be against the compressor wheel. Its like the difference of trying to breath through a wrapping paper spool vs a toilet paper spool. Shorter makes a noticeable difference. Now think of what the difference will be with a turbo hooked to the end of it. You should get better spool up with a shorter intake pipe. Intake temps may differ slightly, but you should still show an advantage over stock closed airboxes. One thing that is popular is to get some thermal hose and zip ties and run a ventilation tunnel from somewhere around the front end into the side of the cone filter. That's a popular thing to do with open intake filters. Vented hoods, cat removal, big radiators and intercoolers....heat shouldn't be a problem