A few more questions:

Assuming the A/C is completely shot, what is so awful about this dreded servo I keep hearing about, and how is it different from the later HVAC systems on the Turbo W123s?

Is it difficult to adjust for loose steering?

How does one adjust out hard/lazy shifts in the transmission?

Are the window switches on the earlier W123s with power windows worse than later ones?

Lastly, if we're talking specifically about NA 300Ds (1977-1981 and all years for the occasional grey market car), what years are better or worse than others?

Thanks to all who have replied!