If anyone feels like weighing in, please do...

I'm looking at cars for my sister. Options include:
1992 190E 2.3 5spd with 83,000 miles! Asking $8k.
1987 300d with 130,000 miles! Asking around $7.5k
1987 300E with 120,000 miles. Also around $7.5k
1983 300D with 130,000 miles!!! Bout $7k

Any thoughts on better years, models, etc? I personally lean toward diesels.