Thank you, gents.
Chris,
So far the only additions I made are visible on third photo - narrow band under the long narrow former on top and some plate between those parallel lines. I also added riveting (now I see that one came loose..).
I will try to illustrate how I made them down the road - didn't think about getting a photo...
There is plenty of surpluss color included in the model plus I'm using a second kit as reserve of spare parts - as I said, I never built a tank before so I expect to make some dumb mistakes