Headunit and Processor Install
For this setup, I needed to have a 4 way active crossover, I also wanted to have a strong EQ section, but space was also at a premium (I used to own all ID rack mount processors - and they were huge).
I was able to narrow it down to two setups that I wanted - Either the Pioneer P9 combo or the Alpine H700.
Let's start with a look at the factory dash:

The headunit allows for a full din unit, but the area behind the hvac control below it is only a few inches deep. Both units are mounted to a "carrier"
I started by modifying that carrier and building brackets to center both units perfectly in the opening. Here's a look at the results:


With the units mounted, I could get started on the new trim panel. I wanted it to look as factory as I could, so I started with a factory radio blind and a manual HVAC control. Some CA glue was used to fuse the two together. I then "roughed out" a hole for the faceplates:

Here it is with the sides and bottom added in with some wood strips. I also added some dynaglas to fill in the holes where the round knobs were on the manual climate control.

Then some bondo and a lot of sanding:

Then I threw a quick guide coat on it:

So there's still a lot to do, but for two days of working part time on it, it's not looking so bad. This is my first try at a project of this sort, so-far-so-good.
I need to clean up some of the edges, the top corners, and a few divots here and there, but nothing too bad.
Here's a few shots from the back side of the piece:

I just used some simple flat black spray paint and held the can about 12-18" from the surface to get the texture right:
And the processor brain in the trunk:

The wires have not been cleaned up, but you get the idea.
And some night shots that people requested:
The color match looks much closer in person, only the Alpine pieces are a bit brighter then the BMW lighting.