I would have guessed you did 80 or 90 km/h, maybe sometimes a bit faster
I have gotten an eye for that from my own videos
I really like the way you drive on snow, it shows that you know what you're doing. Going sideways or trying to drift on snow and ice will only sooner or later make you having a close encounter with the ditch, a guardrail or a tree. It's easy to impress people in winter with "drifting", while in truth they're just showing off or trying to sell their struggle with the car as driving skills.
You made a very good demonstration of how to properly drive on snowy roads: Quickly but not careening, concentrated with everything under control and -- most of all -- with the right tires! They way you drove there, isn't possible with summer rubbers.
Here's a winter video I did in December 2009 with a BMW X3. It wasn't equipped with studded tires but "normal" winter tires, that also work on dry roads up to 240 km/h. The roads were covered in a thin layer of snow, which sometimes had ice beneath it. So studded tires wouldn't do any good anyway:
[video=youtube;VcqC-t_6mgo]http://www.youtube.com/watch?v=VcqC-t_6mgo[/video]
On a side note: Studded winter tires are not allowed here, since the damage they do to the roads, exceeds their benefits by far. Most of the time we don't have a constant snow surface. As far as I know, only snow ploughs are allowed to use them and there is a certain spot of Germany near Bad Reichenhall in the Alps, where it still legal for private cars. But then you are limited to 50 km/h and have to have a
sticker on the back of your car.
When you get to an area, where you can't go on with snow tires anymore, there is still the option of snow chains. In certain conditions in mountain regions it can even become mandatory to use them.