These were original from my '88 944 Turbo S.  I was going to send them to Koni's authorized shop (Performance Shock Inc.) to rebuild, but I bought NOS replacements instead.

Struts:
951 343 031 32 - Left Strut  
951 343 032 32 - Right Strut
For comparison:
  - ~$1000 per side New from Pelican Parts and 944online
 -  Found the left used for $526 on eBay

Includes spring height adjustment hardware:
951 343 521 00 - adjusting nut (x2)
951 343 525 32 - concave washer (x2)
(new from my dealer cost me  ~$300 for the set)

Asking $400 OBO, plus shipping.