Other than seats (and airbag-- waiting to make sure the steering wheel is straight to put that in), the car is finally back together. I'll be putting at least the driver seat in today or tomorrow.
This project spiraled WAY out of control. As in, I spent 100+ hours on this. I'm not going to say I'm glad I did it (sooooo much work), but I am going to say I'm super excited for the results!
In total, the project consisted of...
-remove all factory stereo modules, the stereo wiring harness, and all factory stereo mount brackets. Replace with Avin (which has all the stock module functionality built in) and make a new (tiny) wiring harness for the speakers, plugging them directly into the Avin
-do the above without altering the factory chassis harness at all. I did this entirely, 100% with the Avin only connecting to the chassis with the factory 7 pin chassis to stereo harness plug behind the dash. My goal here was to not have the chassis electronics be compromised in any way. This harness has everything you need for the Avin-- ibus, interior light dimming, ignition power, antenna power
-fuse all aftermarket electronic systems through new fuses in the factory fuse box. No vampire clips or inline fuses exist on my car any longer
-integrate aftermarket system functionality to factory buttons
-wrap all wiring bundles (OE and aftermarket) in OEM fabric tape, secure all wiring to the chassis with OE mounting hardware.
-relocate battery to the "drug bin" The idea here was that the 5.7 lithium polymer battery I'm running isn't meaningfully contributing to weight distribution, but the 8 lb battery cable that runs from the rear of the car to the front is making it heavier.
-relocate and downsize the washer tank to the drug bin. This car is no longer a DD, and never sees winter use, so I don't need anything like a full size washer tank... but I also don't want none, in a pinch. So, I have a ~1 pint tank in the drug bin now, as well. With the stock tank being in the front bumper, this should restore some of the 50/50 lost from not having a heavy battery in the trunk. It'll also make it easier to add brake ducting down the road.
And, add a ton of functionality via the Avin Avant 3, which is the first head unit that's look stock enough that I was comfortable running it in my car:
-CarPlay
-Waze
-YaV1 to add GPS filtering to the V1
-Extra gauges and code pulling on the fly via Torque
Between the seats and the electronics reduction (without functionality reduction), the car should be well over 100 lbs lighter
(not including the battery).
Some pics...
New, Harmon Kardon branding free, speaker covers
Increased trunk space carpeting (no door/rack for the CD changer/nav)
What's behind that carpeting now
Vs before (not my car)
New battery location, with the washer tank visible (pump not installed yet)
And in the area where the battery used to be installed, it turns out BMW makes a deeper storage bin! Key pictured for scale.