What happened to your motor? Did it toss a rod or did it just stop running one day? Is it rebuildable?
If you source a stock d15 it is going to be 22+ years old, with old seals and old sensors, etc.. You are just inviting a headache.
Your best bet, I would think, is to hit up A few engine rebuilders and get prices from them. It'll eat most of your $1200 if not more, but you will have a fresh, new motor with zero issues and fresh gaskets in it. Then drop it in yourself. It isn't nearly as hard as you think it is.
Personally, I would source a ZC from Hmotorsonline.com and install that.