Yet another thread abour radio upgrade

[notech]

Hello guys, I have searched all over but couldn't find what I am looking for:
I want to swap my old CDR23 with an aftermarket unit.
My car is an European 986S - MY2003 with CDR23, CD changer and standard ampli (its not BOSE I believe) all run on MOST.
I removed the CD changer and Radio, been able to wire the new aftermarket unit to power on but wasn't able to figure the speakers connections.
I have a C1 connector with different wire colours and pinout.
Only four wires! Yellow, Red and white, Green, Black.
Also do I have to close the MOST loop to "power on" the speakers?
Any help really appreciated!