So I am toying with the idea of replacing my factory headunit with an Android aftermarket one.

I've done some research and searching here but I have a couple of questions:
1. Does the Axxess adapter box that comes with the Metra kit have a connection spot for the ASWC-1 or does the ASWC-1 tap directly into the factory wiring harness, it seems like it is the later.
2. Assuming its the later, I have a PAC-RC that I pulled out of my Saab when I removed the Android headunit out of that, it appears according to Pac's instructions it should also be compatible with the RX8 (in fact it appears to use the same input wire too), any benefit to not using it vs. buying the ASWC-1. If I have to tap into factory wires with either then I'll just save the money, I was only considering the ASWC-1 if it actually plugged into the Axxess box and made wiring super simple.
3. My Android headunit has RCA outputs and my car has the Bose system, from what I have read here is the Bose system expects low level inputs (i.e. RCA from the HU), I'm assuming with the stock headunit they run through the stock connector. Are all the speakers in the car ran through the Bose amp or only some (I know in my Saab only the factory door speakers ran through the amp, so it needed high level outputs to the dash/rear speakers and low level to the door via the amp).

 

1) It taps into the factory harness. I grounded mine separately recently, as it kept being flakey due to it sharing a ground with the HU (I know, shouldn't share grounds; I did the initial wiring 4 years ago in a huge hurry, lol)

2) I don't see why it wouldn't work with the 8.

3) I'm pretty certain the Axxess box takes care of this (you just wire everything to the correct wire from the HU's harness). As far as speakers and what the amp controls, check the sticky. I do know the door speakers have their own amps. Not sure of their high or low level (nor will I care when I eventually gut the Bose **** out for aftermarket).

 

Thank you, I actually thought about this a little more and I'm guess the SW controls are just the resistor array kind rather than a serial/bus transfer. In that case I may be able to wire directly to the Android headunit since it expects the resistor based controls via the wires for SW control input (on my Saab this worked with the exception of one button, hence why I installed the SWI-RC). I guess I'll try without it first and then add it if necessary, but you are right it does appear like it should work instead of the ASWC-1

OK the way I understand the BOSE system to work is that the headunit just outputs a standard 4 channel signal but then the BOSE amp is more of an amp/crossover/DSP taking that 4 channel input and sending it out to the various speakers and also onto the door speakers that are woofers and get there own amp?

I have read of some people suffering with distortion and loud volume (even at what is effectively a low volume level on the HU) when connecting to a BOSE system, it would be nice if the AXXESS box took care of things, but in their instructions they make no mention of setting the system up for BOSE or non BOSE so I'm not sure how it would know. My assumption is that the BOSE HU outputs 4 channel low level outputs and the standard HU outputs 4 channel high level, does this seem right?

 

I have an S2, and I'm pretty sure the Bose wiring is the same. I connected the factory speakers to the RCA pre-amp outputs in the new HU, it's working perfectly.

I used the PAC RP4-MZ11, it came with rca plugs and everything, I just had to connect the red, black, yellow and blue wires to the HU and that was it.

 

Thank you, I think I am going to go with the resistor padding method and use the speaker outputs from the headunit, this should make the wiring a little bit cleaner (I wont have 4 pairs of wires on both the HU wiring loom and then on the AXXESS box not used). My headunit also has pig tails for the RCA outs so I can just not plug those in since they wont be used, that means less clutter of wiring behind the headunit and I've heard a few people have had alternator whine issues using the RCA outputs to the BOSE system.

I have ordered a spare Mazda wiring adapter so I can steal some pins out of it (I understand the AXXESS box doesn't have pins populated in the n and p (SW1 and SW2) spots, I'm hoping I can just connect those directly to the SW1 and SW2 inputs on my headunit.

 

So I am a little confused by the wiring on the Axxess box, seems to be duplicate RR speaker wires, I have one pair of green (green and green/black) that come out of the orange plug/socket with the other speaker wires (white, purple and gray) but then there is another pair that comes out of the Axxess box. The ones coming out of the box are also labeled right rear speaker +/, seems like they are duplicate?
Also I have an orange and orange/white wire coming from the Axxess box, I'm guessing the orange wire (illum/dashlight) goes hot +12V when headlights/dash lights are on, the other orange/white wire is labeled dimmer, I'm assuming this is a PWM or 1-12V variable signal depending on dash lighting intensity. My HU (a generic android one) doesn't have dimming LEDs, they are even on or off (the screen also dims a fixed amount when the buttons light up). I assume I just want the orange wire, since the HU wont really handle the variable input well.

Other than that I have wired the speaker connections from the head unit to the harness socket in the kit via way of some pad resistors (I believe this should take care of dropping the high level speaker output from the android HU to the line level input the Bose amp expects - this seemed like a more reliable way to do it with regards to alternator whine vs going RCA to wiring harness).

 

So I got it all installed, good news is I didn't need an adapter for the SW controls, just connected the SW1 (pin N IIRC) to the Key 1 wire on my new HU harness and SW2 (pin P IIRC) to the SW ground wire on my HU harness.
I connected the speaker outputs though some resistors and volume seems reasonable with the BOSE system and it sounds good, no alternator whine or popping when changing inputs, etc.
The 3 main issues I had were:
1. My HU didn't fit the opening in the Metra dash kit, ended up taking the Dremel to the headunit bezel to get it to fit (I didn't want to ruin the gloss finish on the faceplate) - I'm not sure if Metra is really to blame or rather the Chinese for building the headunit (or at least the front bezel) to maybe not proper 2din specs.
2. The instructions and brackets aren't worth a damn with the Metra kit, no explanation of where or how to mount the brackets, I ended up having to pull the center vents and put the tabs on the side brackets underneath the tabs for the screws on the vents, also the supplied rear bracket/support is useless, my headunit isn't full depth so the stub didn't reach the hole in the back of the dash, maybe they should supply a bracket with a longer stub that can be cut down if need be for shallow headunits.
3. The USB extension cables for the headunit were barely long enough to reach the middle part of the center console (behind the cup holder) so I had to be super careful with the routing of the wires.

With maybe a better fitting headunit and more instructions of Metra the thing would have been a breeze to install, at least I had plenty of room to install the AXXESS box behind the radio and plenty of length of the wiring so that was good. Fingers crossed but all heater controls work and I was able to set the time and personalize the display with no problems.
Wifi Antenna is tucked behind the plastic knee panel on the drivers side, might move that to some where better.
GPS antenna is hidden under one of the LATCH top point covers in the back and a backup camera hidden just above the rear license plate.
Oh and the OBDII dongle runs to the USB ports that are in the center console.

I'll take some better pics when its light out, but here it is for now:

 

OK here is a better daytime pic and a tweaked theme.