Need some advice

I need a commuter car for my wife and I. She drives at least 25K a year. I really love those 300 Desiels but don't want to get into another maintenance nightmare like our C280 has cost us.

My questions are

1. How reliable are these models - mid 80s - 300 D ?

2. When purchasing one what problems are common amoung these that I need to be aware of? Any particular model to stay away from ?

3. How many miles should I expect to get out of one? I do all the regular maintenance.

4. Would this make a good commuter car?

Thanks in advance.......