Go for the 1991 300SE.

Both cars are W126s, but 1991 was the last year of production for that series in the U.S., hence all problems were completely (or almost) solved at the time.

Also, the SE has less mileage, and that's also a +

I owned a 300TD for 18 years, and although I love Mercedes diesels, you really never get used to the slow pick-up and the peculiar smell from the exhaust.

A. Rosich
S320, 1998
E320T, 1995