Which would be an easier swap into a 98 EK Hatch -- a Z6 or Y8 head? How would I go about wiring the head up since the car is OBDII and a Z6 head is OBDI?

 

y8 is easier if you are going to put it on the stock y7 block.

 

Going to pretty much build a Mini Me for now -- should I just get the wiring harness from an EX and swap it all up? it would be easier to hook everything up without splicing the harness right?

 

If you want to do that you can, but I just used my stock y7 harness. All I had to do was re-wire two of the IACV wires and run 4 tires from the IACV, knock sensor, vtec oil pressure, and vtec solenoid to the ecu.