Yeah I do remember using a single ground wire, but i dont remember what the colors were or anything. And my car isnt here, i am rebuilding the engine so :/ cant really go look at it. Ill look in the wiring diagrams later if i get a chance. Mine is also 90 so colors should be the same.
Basically i just cut a old pair of rca cables close to the connectors, then spliced the wires together with nuts. I made good connections and put it all together, then went to test it out and one of the speakers wasnt working. So I pulled it out again, stripped more off and made sure it was really good, put it back together and it worked. They sound good just not as loud as the other speakers really, needs to be more bass.