reply to 190E2.6
Yes, they are a bit rare. My turbo is the first and last I've seen in North America, but I have seen them overseas. In fact, I'm led to believe in Europe almost half of the Mercedes sold are diesels, even now. I was recently in Portugal & Spain. My little Opel rental was flat out at 170km/h. I was constantly passed by new C Class 220 CDIs doing about 200km/h (120 mph for you Americans [

]). So there is no shortage on a worlwide basis, it's just here that's the problem.
As far as being rare in US/Canada, I believe it's likely two reasons. Recently, California (in their usual brilliance along with sealed beam headlight laws etc?) have attempted to outlaw diesel vehicles. Fortunately for the diesel lovers like myself, the whole scheme has backfired. They placed new emissions requirements on diesel cars they thought would be impossible to meet. Naturally, Daimler Chrysler went back to the drawing board and in no time had a motor that could exceed the new specs (aside from the fact they burn less fuel, new diesel emissions are much less harmful than the emissions from petrol motors - this could explain why pollution is much less of a problem in Europe than it is here in NA?). The second reason is that MBNA are under some illusion that new diesels won't sell (because MB should be a luxury vehicle here, and luxury vehicles are not diesel?). So perhaps one of the morons at the MBNA head office could explain why there are so many Jetta TDIs on the road? In other parts of the world MB diesels are available in everything from A Class, to M Class, to S Class to G Class. If you are interested in old 190 diesels, they are around here, you just need to look hard for a while (I saw a couple around Toronto when there recently). Don't expect to find the turbo however, I think you'll be struggling.
In regards to your other question on snow tyres. I have a set of Nokian Hakkapelitan on both my winter drivers which stay on the cars all year round. Nokian are a Finnish company who make excellent tyres (my ones are the only all season tyre available in Canada that are also snow rated). I have had no problems in winter with either car. I live on the side of a mountain (1000ft elevation gain from main hwy to here) and have passed my neighbours' trucks stuck in the slush at the end of my street on a number of occasions. I find the 190 a great car in snow (until the turbo kicks in and I'm sideways [:0]).
Oh, and BTW, the mileage is about 217,000km - so there's quite a bit of life left in her yet [

]