Hi The_Saint,
With regards to the original maps that came with the unit, if i am not mistaken, it came with a set 2011?Q3 R3 NQ maps...
After reading around 500+ post, and tonnes of researching...
There are 3 main map providers, HERE / NQ / Tomtom, the R3 or 83 on the maps indicates R3 = iGo 8 (Release 3) or iGo 8.3 and 83 = iGo 8.3.X or later release. So essentially, if you have iGo 8.3.X or later, you can run any of the R3 / 83 Maps
Now on to the maps itself, there is little differences between each of the map providers, but I have found with TomTom maps, it is slightly clearer and the 3D buildings display + POIs are better (at the expense of storage space, maybe a few mb more)
So if you have a 8gb microSD, you can fit the entire europe map onto it, it think its around 5gb in size.
When you do download the maps, you will need to place the files into its own folder, search "where to put different iGo files" and its the first link
as for the iGo maps - search "GPSpower TomTom 2014.09 Europe" and again its the first link where you can get access to the maps
(I cant paste the links directly as I only have 1 post lol...
It may be slightly confusing at first to understand all of the map updates etc, so feel free to msg back and I will do my best to answer.
PS - My iGO version is 8.3.5