00 Navigator Full install

I have a 2000 Lincoln Navigator.I want to change the headunit to a KVT-911DVD.Also change the 4 door 5x7s and add a rear amp and sub.Is there a factory amp in this truck? Anyone know where?I assum it whould need to be bypassed for all aftermarket, right?I know there is an amp for the factory rear sub, but what about the doors?

Is it posible to use the factory amps? ex: Remove the old haedunit wire it to the factory harness, or is the factory headunit line level output before it hits the facorty amps? The Kenwood kvt911dvd head unit is 45w x 4 max / 22w x 4 RMS.

If you're installing all new speakers and a new head unit, you might as well just run new speaker wires directly from the aftermarket head unit to each speaker location, ignoring the factory speaker wires/harnesses/plugs at each location and instead going straight to the aftermarket speakers' positive and negative terminals.  This may sound like a pain but I think it'd end up being a lot easier and sound a lot better in the long run, than mess around with bypassing the amp and getting the correct integration adaptors and stuff like that.

If you're gonna be adding your own aftermarket amp and sub, you can forget about the factory amp and sub as well.  Just run RCAs from the head unit's non-fading preouts to the aftermarket sub amp.  Make sure you don't run them next to the amp's power cable though.