Question regarding different units within different nations.

I notice in a couple of gameplays that some nations are using different tanks/aircraft/ military units in terms of the tech tree. I will assume that they are different because of the country origin of the tech. For example, if you are using Germany, for their level 3 Heavy tank they have the Maus, while Soviet Russia has the IS 3. I think I will also assume that the stats are identical as well and don't matter what origin of country did the unit came from.

Several questions:

1.What are the different country tech are out there. So far I only seen Germany/Soviet Russia/ and UKs. I notice that some countries have copies of some of the main Axis tech like how Yugoslavia's tech is identical to the Germans since they also use the Maus for their level 3 heavy tank. I wish to know how many different unqiue country techs are out there. I just find it such an interesting touch and giving each gameplay a slight unique experience as oppose to S 1914 where everything is identical for every nation.

2.Correct if I say this but, as I said earlier I will assume that the "different" techs are only for show but each of their stats are the same, even in the same level. Is this true?