I have just bought a 2002MY WRX 5-Door and want to install a cd multi changer. I have a clarion that I took out of my Accord Type R, which matches the spec in the options list, but do I have to change the head unit or will the factory fit control it. Also with the new units being larger can you get an adaptor plate.

I think that you will find that you will have to get a Clarion head unit to work along with your Clarion changer.

Is the make of the current head unit unit still Phillips? Because if it is and then you could always try and get hold of a Phillips changer.