need info on a/c setup

summer's coming and i'm looking to put a'c in the wagon.i was looking at the unit that mounts under the dash and i was wondering if this is a self-contained unit or would i still need to get a compressor,condensor,dryer?what all would i need to run this style?
classic industry has a complete kit for $1100 that has vents that mount under the dash and it also works as a defroster.
which style would do a better job in cooling down the interior of a wagon?

thanks