I have a obd-1 pr3 ecu from a '94 jdm del sol. I know the obd1 pr3 ecu seems to be rare, and i would like to have a p30, but i don't and this ecu should work. My question is... are there any wiring differences between the p30 and obd-1 pr3? If so, what would they be.

 

Nope....no differences at all.
All Civic/integra OBD1 wiring is basically the same scenario.
This rare, OBD1 PR3 ecu is exactly like a US P30 ecu, only difference is the casing the PR3 part number sticker on the side of the ecu. that's it. You should be fine with this OBD1 PR3 ecu.