[kuehl]

The question is what is "AC compressor is buggered. "?

Does he mean its not getting power to the clutch.
The clutch is not engaging.
The compressor is noisy.
The compressor can't pump properly.
The compressor is leaking.
Broken ears.
etc....

There were 2 variations of Nippondenso compressors on the 944.
The 6E71 model from 83 through 85/1, and the later 85/2+ 10P15E model.
There are different variations of both models in terms of mounting ears
and clutch.

So, clarify the bugger!