This from another thread in the Porsche 924/944/968 Technical Forum.
It would be safe to assume the compressors were the same.
Question about the Portable Porsche Air Compressors
Quote:
Originally Posted by KLR
The air compressors were added at the dealership before delivery. I think that this was to avoid theft while the cars were being shipped across the atlantic, sitting on the dock, etc. There were two basic styles: the cream colored compressor made in canada and the black compressor / case that you more often see advertised on ebay. Which one you got depended on your luck, although I'm sure that it varied somewhat by year.
Below is a page from the 1983 dealer accessories catalog that shows the canadian compressor, so they were handing them out at least from 1983. My 951, which was sold at Paul Miller Porsche in northern NJ on March 31, 1988 and probably delivered there sometime in June or July 1987 came with the canadian compressor too, so they were still putting the cream colored compressors into some cars into the late 1980s. The more popular black ones were also being handed out in this period.
If your compressor has a part number that starts with 996, I would imagine that it was added by a PO after 1999.

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