b18 swap into 90 CRX dx

Hi i'm looking into buying a CRX with the swap already done but it needs "wired up", can anyone tell me where to buy a harness or how much it would cost or any difficulties I could run into. Thank you. Oh and beyond it being out of an Integra and a 1.8 I don't know which motor it is or variant or whatever.

what year is the motor in the car ? Is it an obd0, obd2, or ob1