Stock system plus advise

[M4Lki3r]

I am planning my install for my CarPC and an audio setup to go with it. The CarPC I have all sorted out, but need a some information about the stock system and would like a little advise about other components. I will be removing the head unit completely and using strictly the PC for audio/navi. The speakers will be staying stock (for now). I also am going to be installing a 12" sub at the same time. So here are my questions...

Should I use a 6-channel amp or a 4-channel and a mono for the sub?
What are the stock speakers rated at?
Someone suggested that I use a sound processor to connect via SPDIF instead of the three 3.5mm jacks. Any input/advise on this?

[biggie5252]

I would probably say go with a 4 channel and mono amp, since most monos are class D and most 6 channels will be class A/B. The class D will require less power. Other than that, it really doesn't matter.

I would agree with the SPDIF. Digital is usually better than analog.

[scanevo]

if you go with one am for the whole system check to see if the channels 5 and 6 are seprated from the other 4. sometimes they have a second circuit for the 5th and 6th channels or they may just have a mono 5th channel