I'm putting a new set of component speakers into the front doors of my 1994 Deville, and I need to know where the factory cross-overs are located so I can switch them out with the new ones, if that's even a good idea. The cables run from the head under the carpet and seem to go back towards the trunk, but I can't tell where they come out, and they're split into woofer and tweeter cables already by the time they get to the front doors. Maybe I should just swap the speakers and leave the factory crossovers alone?

Sub-Question:
I had my head unit upgraded years ago before I knew a thing about anything, and the guy who did it disabled 3 of my 7 speakers in the process! Only my front doors and rear decks are getting power. Is there a way to get power back to those speakers without going back to the factory head unit?