Help on wiring and ECU?

Hi I have a full K20Z1 swap out of an 05-06 RSX Type s and I’m installing this into a 99 Civic. I’m finding that I can get a reflash on the K20Z1 ecu through hondata for swaps but can’t install kpro. Do you know if that reflash bypasses the immobilizer, and if so what do I do for a conversion harness? It seems like people are using the K20Z1 engine harness but every conversion harness I’ve seen says it won’t work with the 05-06 RSX engine harness. Is there a harness I can use for this or do I have no other choice than to get an ECU and engine harness from an 02-04 RSX Type S?