On the VSS Buffer box, I know what most of the pinouts are.
From http://la.rsson.com/speedo/speedo.html
Sensor related:
Purple - from sending unit
Yellow - from sending unit


Pink with black stripe - switched 12V power

Green with black stripe - to speedo
Black with white stripe - ground

Now there is Brown and Red with black stripe

as seen there.
I am told that the ECM needs a signal from a buffer and the old gage cluster had a pinout for "BUFFER SIGNAL TO C3 COMPUTE" and "C3 COMPUTER GROUND TO BUFF"

I'm guessing that the brown is for "BUFFER SIGNAL TO C3 COMPUTE" but is it safe to assume that the red wire is for "C3 COMPUTER GROUND TO BUFF" ?