Don't worry about flaming here, we all get along. Except for Furious. He is some sort of punk guy pffffft (lol jk furious). Yes you have posted in the wrong forums, but have no fear, a moderator will move it to the corretc forum. You have an e36 coded model. That is any 3 series from 1992 to 1998 or any M3 from 1995 to 1999.
I do not really know in which direction to approach you question. Good brands are; Alpine, Blaupunkt, Pioneer, Sony
Those are just a few off the top of my head. Are you looking for just a basic CD player to set things up? Maybe a certain Wattage ranger? 40 X 4 is the minimum you should go in wattage. 50 X 4 is a good amount. (thats 50 watts at four speakers. Total 200 watts. Are you looking for any extra features? a remote? slide down screen? pop up screen? faceplate interchanging?
1995 BMW M3 Turbo - Dakar/Black