You go into the data editor then go to the model tab. Find the unit you want to change, then there should be a color option that by default will be set at "255,255,255,255" - typically I have seen 3 numbers for RGB, but it may still be RGB and just have black or white as an extra. 255 is the max number, you will have to lower respective colors to change the shades so play around with those. Sorry I can't remember exactly which is which.
I don't mean the player color but the color of the whole unit
@gregv21: Go
You go into the data editor then go to the model tab. Find the unit you want to change, then there should be a color option that by default will be set at "255,255,255,255" - typically I have seen 3 numbers for RGB, but it may still be RGB and just have black or white as an extra. 255 is the max number, you will have to lower respective colors to change the shades so play around with those. Sorry I can't remember exactly which is which.
Go to actor of your unit -> events and add
UnitBirth.<UnitName>
SetTintColor R,G,B
You can mess around with the blend duration and timers to make your unit swap between different colors :D