Anybody knows any sourсe except of Mazdaparts and RPMstore to buy AV nav switch and other firmware to hook up DVD, rear camera etc.?

I just cannot get any answer from Mazdaparts, it seems my inquiries somewhere in SPAM or something and RPMstore just cannot provide with audio adapter.

One more answer. Are there any way to hook up to navigation/AV switch any scan gauge to see dates from engine on navigation screen not separately?

Thanks in advance for any help!