I always avoid buying used cars at new car dealerships... or car dealerships period. IMHO best prices are on the street (private owner) as long you have a clue as to what your buying.
There is an 05 CDi by me with the following:
2005 Mercedes-Benz E320 CDI Sedan odometer: 95600
2005 Mercedes E320 CDI Turbo Diesel Sedan Silver with Gray Leather Int. 95k miles

CARFAX Certified (NO ACCIDENTS, FLOOD or SALVAGE HISTORRY) Drives 100% NEW TIRES and BRAKES, Needs Nothing Except a new place to call home, This Car get very good on Diesel gets 40 MPG

CARFAX Report can be emailed to you upon request

Featured Options Include: HID Xenon lightsNavigation, Premium Pkg, Winter Pkg, Harman Kardon Sound System, multi contour drivers seat.

I just don't want to spend that kind of money right now. Half the miles of the one I inquired about but is it twice the car?
I personally won't be racking up many miles a year. As I said before, I'd be lucky to put 5k miles a year on the car. I do most of my driving with my Toyota Tundra and my wife drops an picks up the kids from school 1.5 miles both ways plus shopping and other errands. My thinking is I buy a used "cheap" MB diesel an keep it for a year or two. If the wife likes it enough (which I am thinking she will) then I buy a newer model with low miles and keep it till it dies.