Ok, so this car could get you $150k+ in good working order. Problem with valuing it is the effort and money you will need to put into reconditioning it. It could have extremely low miles since you said you’ve never seen it move. You would need a PPI on it before anyone could suggest a price.
Here are some recent sales to give you an idea:
https://bringatrailer.com/listing/1998-porsche-911-carrera-s-coupe-33/
https://bringatrailer.com/listing/1997-porsche-911-carrera-s-coupe-21/
https://bringatrailer.com/listing/1998-porsche-911-carrera-s-coupe-29/
https://bringatrailer.com/listing/1998-porsche-911-carrera-s-coupe-28/
box of assholes once again the voice of reason