Honestly, its way less of a headache to get a PAC AOEM-MAZ2 adapter, its plug and play and it hooks directly to the TAU. The TAU is on the passenger side, easily accessible by removing the glove box. That's what I did, I ran my Power cable through the hole for the clutch cable, routed under the...
What about the PAC AOEM-MAZ Mazda Bose Premium Sound System Interface. Although it was discontinued, its worth a shot.
https://shipsound.com/products/102751