Mercedes Benz repair: 1980 Mercedes-Benz 300 SD, mercedes benz 300, engine leaks

Question
I am thinking of buying this car, but need an expert's opinion on
the owner's description:

" it has a significant engine noise that has been diagnosed by my
mechanic as a scored cylinder caused by a broken ring in cylinder
number one. Engine leaks some oil, and does smoke some,
although not excessively."

Is this a DIY repair?  If not, what can I expect to pay a pro to fix the
thing?

Answer
Yes, it is a grade TEN DIY = roughly $3,500 in parts and tools.
The big if is:
Are you (in skill and tool set) close to being a master mechanic?
If you are not, offer $1000 for the car, and drop a good used engine in it for $600, or RUN AWAY from it.