porsche cayenne base

I have a customer from out of town who has a 2005 Porsche Cayenne with the Base model sound system.  In-dash single din (-ish) cd player with the Bose audio.  His amplifier went out and he was quoted $1500 to replace the factory amp.  So his second option is to gut the system and install a new head, amp, speakers.

Question 1: is the factory head-unit CANBUS controlled or can I grab the 12v constant and acc at the headunit?

Question 2: The door speakers are listed as 5 1/4"'s on Scosche and 6 1/2"'s on Metra, so which are they?

I unfortunately do not have access to the vehicle and at this point all I know is that I'm building a custom kit to fit the deck, but NOBODY knows about the wiring in this vehicle.

Thanks in advance.

Some of the newer Bose systems actually use 4 ohm speakers.  You may not have to change the speakers.