The rear window not rolling down is a pretty easy fix - maybe some better details about the SLS problems would help potential buyers. Wherever you end up listing this - a few good engine shots can tell volumes about the car and how it was maintained.

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1987 300TD named Klause
1987 300TD named Spouse
1987 300D named Seabiscuit
1980 300TD names Chloie (now sadly gone)