I have a used water pump for a s14, it should fit the s13 dohc, it was in good working condition when it was taken off. If you're interested, [email protected]

I'm also going to shoot myself in the foot by telling you about pinnacle nissan, it's a dealership in Arizona I tihnk? Search pinnacle nissan on google, go to their parts page, they have awesome wholesale prices, and good service. you can find just about any OEM nissan part there at a much lower price than dealers here.
I think they sell the pump for about $80, I'll let mine go for $30. Good luck.