91 Mercedes 190E

My freind is considering trading in his mothers 91 Mercedes 190E (2.6 automatic with 104K miles) at a dealership for another car. The dealership is offering him 7K. I am considering buying the car from him for the same amount, but would like to find out more about the car. Kelly BB is $12,500. It has a new transmission (less than a yr)and the outside and inside looks well kept. It runs very good. He says the timing chain needs to be replaced which will cost around 1K. What do you think? Does this model have a history of mechanical problems? Are they high maintenance cars? Are parts extremely expensive. What should I look for if I consider buying it? Is 7K a good deal? Thanks for any comments.