there are basically 3 different types of intakes....
cold air intakes....what i call "ram air" intakes....or...short rams.
cold air intakes places the filter out of the engine bay to avoid using the hot air that lingers in the engine bay. this is good because cold air is more dense, meaning good for the engine.
short ram intakes places the filter open in the engine bay. blah.
ram is, i dont know the name, so i just call it that; is a short ram intake, but the filter is enclosed in a box. and there is a tube that feeds the box cool air while the car is in motion.
i guess there are pros and cons for each.
having a cold air intake, you have a slight risk of sucking up water. but if you dont drive through puddles....itll be ok.
ram air intakes, they are good because they get cool air, but its only when the car is in motion. so when you are at a stop launching the car, it gets the air that has been cooking inside the box. but you get a short intake tube than the cold air intake.
the regular short ram intakes are just noise makers.
and also the brands are virtually the same. all except Iceman uses metal, where as they use some kinda plastic.
i probably left something out...but that covers pretty much.