Considering 617 vs 603

[MercFan]

I'm considering the following two cars - both of them would require travel outside of my state, which I'm willing to do for the right car... Let me first say that this time both sellers are cooperating very well - which has been the biggest issue thus far in my long-distance-car-shopping adventure...

Candidate#1 is a 1984 300SD - as seen in this ad: http://sanantonio.craigslist.org/cto/1414499663.html
Female driver, odometer broken so approximate mileage about 170K - leather seats, pretty clean inside, no wear on the seats - dash has no cracks. She said the a/c compressor works but the a/c is not cold. The engine bay looks pretty clean, though the aluminum valve cover, cruise look pretty oxidized, not sure why?! Green coolant, the belts and hoses look fairly new. She said the pickup was not as good as the Isuzu truck she had before.... Some service records exist - asking price $1995, willing to negotiate.

Candidate#2 is a 1987 300SDL - as seen here: http://jacksonville.craigslist.org/cto/1422357388.html
The owner has car repair business - this was his mother's Benz from new. She was the only driver until 1 year ago when he bought her a brand new replacement Benz. He sold this car to the employee - carried the financing for him until the guy fell back on payments and the car was repossessed - looking to sell it now. Looks clean in additional photos he sent me - engine bay very clean but not too clean. Proper coolant in the expansion tank. Very clean and shiny IP. No records, but the car was maintained by two dealers in Jax, FL - they have records. Supposedly all systems are working. Appears very clean inside from additional photos. Asking $3500 - willing to negotiate.

So it's between the reliability of the 617 which seems to have been taken care of fairly well and what is seems like a clean, well maintained 603. The 603 is calling my name, but I know the parts can be more expensive and whatever I buy I'd like to keep for a while and use as my DD, including winter driving here in CO.

Advice, recommendations on which one to pursue?! I like the SDL a little better, but I don't want a money pit, if you know what I mean.

THanks,
James