Paul:
Some info that might help you sort out and comprehend all the different products:
1) City Navigator and City Select (CN and CS) - these are NavTech products that support auto-route generation on the GPS itself, they are serial number locked to the specific GPS unit. Because your StreetPilot ColourMap does not support serial number unlocking (it was made before that process was invented), you can't use these products on it.
2) MetroGuide Europe (MG) - this product, also by NavTech, does not support auto route generation on the GPS. This does not mean any loss of functionality for you, because your GPS can't calculate routes anyway. MG map segments are much smaller (in data size) than the comparable CN or CS segments, because they don't have the street attributes, etc. that are needed for autorouting. MG is intended for use in the GPSR's that have smaller memory capacity (such as your SP ColourMap) and is the best product for you. It is also much less expensive than the CN and CS products, which might be good news for you.
3) You referred to "MapSource" in your original post. MapSource is actually the name of the computer program that runs on your PC and is used to move map segments, waypoints, routes, etc. between your PC and your GPSR. MapSource itself does not contain any cartographic data.
Think of the various mapping products (CN, CS, MG) as being different grades of gasoline (98, 95, diesel), and MapSource as being the pump that moves the gasoline from the underground storage tank into your vehicle, and you'll have the general idea.
PanEuropean