Probably around $50k + if documented and no major needs and 5spd since it's a desirable color. A bunch of needs on the PPI should bring the price down, but there are allot ballers ready to drop $50k for a clean C2 Coupe with some issues that are planning on turning them into an elaborate Hot Rod build, Singer etc... If it's either Ruby Stone, Maritime, or Mint expect to pay a $10k premium at least. I follow the market closely and C2 Coupe 5spd cars get swooped up in a matter of minutes if priced correctly.
Here's recent comp on a 93 common color GR/Black, no Cup 1s. 92k. Sold very quickly at full ask I believe.
https://rennlist.com/forums/vehicle-marketplace/1073219-fs-1993-porsche-c2-manual.html