Good questions here! Let me answer them one by one.
statdoc: Yes, that's what were' saying. It will be applicable for both DSP and non-DSP vehicles.
Kryptonite: You are right on the dash speakers and door tweeters, but the door midwoofers are actually a non standard size. They are approximately 6.25" (somewhere between an aftermarket 5.25" speaker and a 6.5" speaker). We go with a 5.25" primarily for practical reasons; a 6.5" aftermarket speaker would be MUCH harder to fit and take quite a bit more work on the customer's part.
The results with a 5.25" are excellent, and there's no need to overcomplicate things, so we stick with a 5.25" -- but include the required adapters to make them fit perfectly. So, as a word of warning, don't just go buy any 5.25" speakers somewhere else, because they won't fit without a custom made adapter!
bigX5er: It is pretty striking how bad some of the sources that sound "OK" sound after you get an audio system in there that reveals everything, isn't it?