USDM Cefiro

I know from reading threads here that most people have had issues with RCA plugs on BOSE equipped I30s and Maximas, usually because the amp/speakers require 4v but the hu's usually have 2v RCA inputs. I'm totally fine with that (I'm rebuilding the car's sound when I have the funds to do so) BUT has anyone had a particular issue where the RCA only powers the sub in the rear deck but not the speakers in the rear doors? It seems really odd to me.

Also, how many people have had the subwoofer cut off after replacing the hu? I seem to be having that problem, and I'm not sure where to look now (another reason why the stock speakers are gone when the funds are here).

This is in an A33 I30. 2001. Long story short, I need this list of questions answered.

1. What can be done (without a PAC) to get the speakers in the rear doors to work?
2. Will the PAC solve all my speaker issues or am I better off putting that $30 in my replacement speaker fund?
3. Do A33s have an amp for each speaker like the A32s do or is it a central amp?
4. How would I go about replacing the amp that's in the trunk without running a wire from the trunk to the battery? Is that even possible, or should I go all out with that amp if it involves running a cable to the battery?
5. What size speakers are in the doors, rear deck and A pillars? It seems to be very well covered for A32s but A33s seem to be left in the dark.

All help is appreciated.