Another update - SUCCESS!!! The Bose amp is out of the car completely and everything is running from the head unit and the DSP/amps I added.
- The output from the STOCK head unit (originally connected to the Bose amp) works great as the input into the DSP. I am using the two front channels (front-left, front-right) as the signal to the DSP, which I am sure could also be used as high-level inputs straight into an aftermarket amplifier.
- I ran the rear outputs from the STOCK head unit directly to the rear door speakers for backfill. It works, but the output is very weak. If I decide to do anything more with them, I'll probably add another two-channel amp for those.
- I tapped into the stock wiring at the Bose amplifier by cutting off the Bose connectors and splicing in my own wiring harnesses with Molex connectors. I used two 16-pin Molex sets, which sounds like a lot, but a lot are required. Just for the audio, at the Bose amp, there are four pairs of input wires, and six pairs of output wires for a total of 20 connections.
- In the factory service manual I found that there is a remote amp turn-on wire for the Bose amplifier. So I tapped into that and am using it to power on the DSP and the two amplifiers. Works great. So there is no need to run a separate remote amp wire.
- I have not installed my dash pods yet so for now I am using the Bose a-pillar tweeters in the front. I believe I have them crossed over at 5 KHz. They are working well enough for now. The plan is to disconnect the tweeters and use those wires to power the dash pods.
- The Tang Band front door speakers are TREMENDOUSLY better than the Bose speakers. No comparison. Very natural sounding output on vocals, bass guitar, toms, whatever. I am very happy with these little guys.
So all I have done so far is set the crossover points on the DSP and the whole thing sounds much, much better than the Bose system. Once I add the time alignment and euqalization (Room EQ Wizard, reference mic, etc.) it is going to sound really, really good. I'm very pleased with how it is going so far.
FYI - You do NOT have to remove the rear seat or completely remove the right hatch trim panel to get to the Bose amp and the connectors. The panel is flexible enough to bend out of the way and get to everything. This ended up being easier than I expected.
Tapping into the stock harness is just a matter of cutting off the existing connectors, and splicing your wiring into the cut ends. It is time consuming, and took about 3 hours to complete. This included double-checking that I had the right input and output wires. There are a lot of connections to make, so it is best to write out a wiring list in advance, and use color coded wires whenever possible. The stock wire colors as indexed by the service manual are a little weird, like several different shades of blue that can easily be confused, so be sure to check colors against the pin outs on the stock Bose amp connectors (the ones that are cut off). Also, use a small speaker to check the output wires from the HU, and use a small AAA battery to check the connections to the speakers; if you tap the two wires you are connecting to each terminal of the battery (just tap, don't hold the connection), you will hear a small pop from the door speaker you are wiring. This does not work well with the a-pillar tweeters, so check those with an audio signal.
Here are some pictures of the Bose amp removal, the wiring harness splicing, and the finished harness with the panels back in place:
Here is a picture of the subwoofer box with the amplifiers, the DSP unit, capacitor, and the mating Molex connectors: