I ditched my OEM intake because the rubber baffles had cracks in them which induced vacuum leaks. I switched over to the intake that tlc4x4 sells (
http://www.tlc4x4.com/2000/Parts/tlc_air_intake.htm). I've run it for a couple of years now.
I did notice a small performance improvement (it's still a 3FE, don't expect miracles

). It's not waterproof and it sucks in hotter air than the stock set up. However, since you mentioned it, it did free up space. I've relocated my coolant overflow resevoir (dual batteries) under the filter and my MSD stacker ignition box next to it. I'm planning on fabbing up a box to isolate the filter from the engine bay.