the last two cars I bought have been one owner mercedes...both were c
class...both were fine cars, 1998 C230 and my current 2005 C340 awd. When I
bought the car, it had about 14000 miles on the odometer, today it has
double that. I negotiated an extended warranty for 5 years or 100,000 miles,
so at present I am covererd through 2009. The warranty will probably expire
before I reach 100,000 miles...but, who knows. So far, there have been no
warranty claims, only routine maitanence Type A and B through independent
mechanics with whom I have been doing business for many years before buying
my first MB.
Bottom line, do some careful shopping, establish your price, using edmunds
or kelly blue book, and negotiate hard. dealers are hungry for deals. btw, I
also got a 2.9% interest rate, better  than any conventional financing.

Sherm