Ford Meteor speaker wire colours

[b1b2b3]

Hey all, I'm not sure if this is the right place to post this, but I couldn't really find any other part that suited the car lol.

My sister has a Ford Meteor, and she wanted to put sum decent speakers in there, so I took her down and got her sum 6x9s. Everything was going great until I came to the connecting the wires part. I only wanted to use the wires that were already in there, to save time on having to run new ones to the front of the car, but when I went to connect up the pos and neg I couldn't work out which colours matched up where. It didn't help that the original wires didn't reach long enough, so I had to use a small bit of the wire I got with the speakers as an extension, and then also used the fork things at the end of the new wire. For some silly reason, or just because I didn't think I needed to, I didn't check which colour wire the small fork was on and which the big was on, so when it came to adding the extensions, I had no idea which to way to wire them up. I then thought that I will just be consistant and wire the negative new speaker wire to one colour on for each speaker, and the postive to the other colour. This turns out to be quite difficult seeing as though each of the 4 stock wires are different colours! So my question is, what is the colour codes for the Ford Medeors original wires i.e. which colours are positive, and which are negative?
I have them all wired up now, and connected, and the speakers seem to work, but I'm not sure that, if I actually wire them up properly, the sound would be better, or is there only one way to wire them up? any other way will just not produce any sound?

Sorry about the long question, any help is greatly appreciated.

Luke