Adding factory navigation to a 2010 Mazda5 Grand Touring

I just purchased a 2010 Mazda5 Grand Touring with the factory 6-disc CD changer. I would like to replace the 6-disc changer with the factory navigation.

As far as I can tell, I will need the following parts:
1. Navigation display unit (I found a unit from a 2009 Mazda5)
2. Heater Control Unit (AC knobs with correct nav-specific trim installed)
3. Nav Antenna
4. Nav DVD Disc
5. Volume knob
6. A few clips, bolts and rubber cushions

The navigation unit and heater control unit are the two priciest items. Before I purchase them, I would like to be certain that vehicle wiring loom for my car has the necessary connectors.
Though I havent pulled mine out yet, pictures I have found of the back of the factory 6-disc unit show that there are two main wiring plugs.


The back of the nav unit appears to have seven.


Two of these seven are the same size, shape and location as the two on the 6-disc changer. The green one should be for the GPS antenna. Any idea what the other four nav unit wiring connectors are for?

Is the base vehicle wiring harness the same for all Mazda5s of any given year?

If this sounds feasible, I will give it a shot and make a walkthrough with pictures to share on here.

Thanks for your help.

Regards,
Justin

For the 2006 Mazda 5 the wiring loom is different for a Navi and non-Navi (I have the 2006 manual). I would assume it is also different for 2010.