Oh I forgot about your second question.
I like the 91-93 300D 2.5 myself. I also own one so I practice what I preach. Of all of them, I like this one the most (except for the repair bills, yikes, its in the shop as i type).
They are not too complicated and can be worked on yourself, not too slow, priced reasonably, etc. Of course if those factors are not important to you, the 99 E300 turbo is the way to go, if you can find one for sale.
I like the S350 myself and was going to get one, and still might to add to my collection, but they have engine problems.
82-85 diesels have a good look, but they dont have a lot of features newer cars have, like my 84 300D turbo doesnt have automatic seats, air bags, anti lock brakes, etc. and its the slowest of the 3. Goodluck