This is a US based answer:
my 2003 Z4 with basic system had 10 speakers:
2 - dome tweaters in the door sail (triangle)
2 - 4" mid range in the door itself
2 - 6.5" full range in the kick panels
2 - 4" mid range behind the seat
2 - 6.5" low frequency behind the seat
my 2006 Z4 with Carver Technology upgrade
same configuration as above BUT speakers are more robust, higher output (perceived), much wider range. Sound a lot better.