I spend most of my time over in the BMW forums, since that's what I own. I'm in the process of upgrading my 2007 to have a 2018 factory navigation system.
While I'm at it, I'm setting up a friend's Mazda with a Carplay upgrade.

I was driving my girlfriend's 09 Maxima (non-bose, non-nav) this weekend, and got to wondering about upgrading her system.
I looked around and found a few options, but they mostly involved leaving an ugly unused screen at the top of the dash where the nav screen should be, and putting an aftermarket system underneath it.

Has anyone found ways to mix this up?
I'm thinking: Put an aftermarket double din radio up top where the factory display is, and install the HVAC controls from an Altima (with the built-in displays) where the current radio controls are.
Anyone think this might work?