No Way eBay!!
1. I had very bad experience with an eBay purchase. In talking with mechanics and shop owners this has become very common. They all have a dozen recent horror stories for eBay purchases. This does not mean that can't get a decent car on eBay; some people here have reported an ok purchase, But I would Not Buy on eBay. I still like to look at the cars though. I certainly would not buy a car unless i could see it, touch it and have it inspected by a very good mechanic. I think there is a reason many of these cars are on eBay. Why couldn't they be sold locally??
2. Take a deep breath-- You seem to be in big rush !! The longer you have to look the more you will know and will have a much better chance of getting a fine car. Are you sure that you want a diesel?? Which model do you want??
3. Is this car going to be an everyday driver? Or a special roadtrip car or weekender?
4. Do you live in the rust and salt zone? This effects the car you buy and how you use it and how often you fix and replace it.
5. If You live in a major urban area and are going to use the MB daily then maybe a late model 190e 2.3 or 2.6 would be a real good choice. I had one, it was a good car just right for city driving it had low miles and was easy to get repaired.
6. Go to all the dealers drive everything. Take some time--a bad car can be very expensive!!