ok i had in my van tw0 12 in a box facing the back sitting against the seats, held in place by two custom boxes that held 6" speakers and had anothe two speakers mounted facing down in the front behind the dash(the holes were already there when i put them in)
very good setup but the speakers in the back were fairly pointless as they sat down too low for a decent amount of sound to get through to the front.
i would suggest mounting a speaker or speakers facing forward in between the seats as that would project the sound forward a bit more.
if you don't have high back seats i'd place them up high behind each seat.
as for front it's hard (almost impossible) to get speakers into the door without spacers if you have wind down windows. at the moment im building some panels to hold my 6" into my sliding window doors.
places to mount in the van can be the doors or the floor behind the driver and passenger (on spacers so you dont mount it to the battery
) and the dash shelf or the dashboard itself if you have enough room.
i've crapped on long enough so that wiil do hope it helped
