1990 Ford Thunderbird Wiring

I recently bought a 90 Bird that had a Kenwood installed, but its fried. The OE power harness is still intact. But the OE speaker/amp harness is fubar. I have looked through ALLDATAPRO and Mitchell on Demand and all I seem to find is the color codes. Which is fine, that is part of what i need. What i cant find is what feeds what. I checked and the colors into the OE amp are different then the colors coming out. Thank you ford. The  vehicle is equipped with "Premium sound" not the JBL system. I would follow the kenwood install, but its so ugly, im afraid to.  About 3 splices per wire. I just want to have it clean when I put the new deck in.

These are the colors to the amp: W/R, BR, P/W, LB, LG, W/O, LB/BK, Y. 

Out of the amp there is : DG/O-W/LG=RF. PK/LB-DG/O=RR PK/LB-PK/LG=LR. LB/W-O/LG=LF.

They are also nice enough not to give the polarities so that i can see if the Polks in the doors are hooked up correctly since they were a cut and splice job as well. The previous owner says this system was a proffesional install, but Im beginning to wonder if thats true. If anyone has any insight to this and could help, I would greatly appreciate it.