Sorry, it's been a while. I'll jump right into it....
So I installed my Kenwood DDX775BH with the Metra/
Axxess Kit GM-MOST-02. (pricey still at almost $300 for the dash kit and harness; I bought both of mine off carID as they were the only ones that had it at the time).
I wound up having a shop do the headunit install because I was lazy af and they had a bar next door (!!). I tore the dash completely down for them and also ran my 6 channel pre-outs to the DSP so they had minimal work to actually do and everything came out nice. With that Axxess kit, the Onstar app controls also still work fine with my vehicle so that's a nice little bonus.
I also added a Sirius XM module (
SXV300) to get my XM back after not having it for a few weeks with the new radio. At first I used the included antenna from the XM module, but reception was piss poor no matter where I placed it inside the cabin/dash because I didn't want to add the damn thing to the exterior on the roof... So I wound up buying an
adapter to use the factory antenna fin on the roof; link for that here:
XMF-SMB FAKRA to 3rd party Satellite Radios :: Car Stereos and components. I bought a 6 foot extension but I'm fairly sure 3 foot would be enough. The cable needs to run from the inside of the dash (above the glove box) where the XM tuner module sits (or wherever you have it placed after installing to the back of the radio) to the bottom passenger kick panel where you'll connect it to the factory XM connector (I believe its the gold/yellow connector down there). Once I did this, the reception is the same as factory, no more intermittent dropouts.
Overall, sound quality is superb now with the new radio and I have a nice looking radio with more features.
Currently I'm working on installing an aftermarket dash cam,
Crux CUL-03. It just shipped out today so maybe I'll give another update if it winds up working out. Pretty sure it should fit on that lip right above the license plate though.
Also, I'm going to sound deaden my floor and roof next (everything else - all doors and entire trunk - is deadened to the max with CLD, CCF, and MLV all layered up) and then make a MDF amp rack panel to tidy up all my amps and wiring (currently in a bit of a rats nest, but not too bad)
That's about it for now. If you have any questions feel free to ask away, I pretty much know this damn car inside and out now audio-wise.
Also a side note for everyone:
Crutchfield doesn't really have an up-to-date list of fitment for either radios, nor speakers for our cars (at least at the time I did everything).
The speaker baffles I used for my new speakers are listed here and DO FIT, same exact bracket/baffle as OEM:
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Front 6x9 bracket for new 6.5" woofer - Metra 82-3005 Speaker Mounting Brackets -
https://www.crutchfield.com/p_120823005/Metra-82-3005-Speaker-Mounting-Brackets.html?tp=2824&omnews=13521804. To ensure a speaker will fit, I plugged in a 2016 Silverado and used that as my fitment guide. My new speakers went in like butter
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Rear door speaker 6.5" bracket - Scosche SAGMHR-634 -
https://www.crutchfield.com/p_142SMH634B/Scosche-SAGMHR-634-Speaker-Mounting-Brackets.html?tp=2824&omnews=13521804