Only been at this about two months, but love the detail and technical info in the game.
Found a great reference manual at Amazon,
called 'Encyclopedia of German Tanks of WWII'
with over a thousand pics of all types of German armor including all the tanks, guns, arty pieces, etc.
If you ever asked yourself "what the heck is a
Hotchkiss?" while playing, this book is great.
Gives all the info and stats. $15 bucks.