1. Also check with Truthunter (Ryan), since he owns a Toyota he should have some insight.
2. I believe most hi-rez players have a built in DAC, but the folks BigAl mentions would know better.
4. I got a smokin deal on some AD W800Neos and love them, but my installer also recommends Morel MW9's, so worth looking into and probably easier to find.
5. I have both tweets & mids in my pillars and can say that while they sound great overall, there is some localization and stage width issues. BigAls truck, Mike Meyers Subaru & Ryans Camry all have very similar installs in that their mids fire up into the windshield and tweeters are either just off-axis firing at the head position or in MM's case firing into the windshield itself... these arrangements seem to lessen the two issues I have.
6. Rear fill is a personal preference and needs to be setup correctly otherwise its just a couple of speakers in the rear deck...
I have it in my car at the suggestion of my installer, and it adds width to the front stage as weird as that sounds.
7. Love me some Zapco A/B amps! There are of course other brands, but IMHO, class D amps seem to have a slight compression to the sound, but everyone hears things differently.
8. I've owned Helix processors in the past and can recommend them as being easy to tune with. Having heard what Ryan & Bertholomey/AfghanVet/Jason were able to accomplish using the miniDSP with DiracLive... I'll just say that DSP is a step above in what it can do.
9. Do the best deadening job you can without going overboard... if you find rattles later on, they can be addressed at that time.
10. Big 3 can be worth it if you are doing alot of ground-pounding, but just a good battery will suffice for most SQ stuff.
11. I've had great results with Acoustic Elegance subs, the key is to make sure that whatever alignment you choose, make sure the baffle/enclosure is SECURELY mounted to the vehicle... did I mention SECURELY?