I second tjts's thoughts on this issue. I daily drive a 91 350SDL. It's not the miles that I would be concerned with (mine has 322k and gets driven 35k a year). It's all the rubber bushings, hoses, wire connections, electric motors, etc that have issues because of age. I've spent a lot of parts over the past year and I still haven't tackled it all.
But that said, I enjoy driving the car enough to make it worth it to me.

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1991 350SDL 350k+ miles