106 - 5 Door - Parcel Shelf Speakers

Hey,

Did a quick search through this group and couldn't find the question
asked before. I used to own a little old Rover Metro and this had 2
fairly decent parcel shelf speakers come with it. When I sold it on I
decided to remove the speakers and keep them for my next car. The next
car turned out to be a little Pug 106 and it's doing me grand. I fitted
two replacement front speakers and shoved the stock ones in the rear
doors.

I've now managed to get hold of a replacement shelf that I've cut up
and popped the parcel shelf speakers in to, I've checked the stereo is
capable of powering all 6 speakers (to be honest, I'm not fussed about
a -loud- system, just as long as it sounds good at reasonable volumes)
but I can't for the life of me figure out the best way to wire them up.

The way I see it I have a couple of options, I could take wires from
the back of the headunit, run them under the carpet and hook the
speaker up that way OR I could see where the wires run to the speakers
in the door and splice in to those. Unfortunately I can't figure out
where they actually come in to the car! It looks like they enter in to
the coving that covers the (front) seat belt mechanism but upon taking
this off I could only see the wires for the doors central locking.

I'm NO expert with this type of thing, so the less work for a decent
install I have to do, the better. Also, whilst prodding around I've
noticed two orange wires that come from near the handbrake and run
under both front seats. Anyone any ideas what they could be?

If it makes any difference it's a '97 Peugeot 106.

Thanks for any help! Merry Christmas too!