Should I keep my engine harness

I have a 94 civic cx hatch and will swap a b18c in. Should I keep my grey engine harness plug that's on the passenger side closer to the engine or get one from a b18c? What about the plug closer to the firewall? And what should I do about the engine harness plugs (the one closer to the engine & one closer to the firewall) on the driver side of the engine close to the shock tower.

Really won't matter that much, you'll still have to do a little wiring either way. The B18c harness will have the vtec wires all the way from the engine to the passenger side shock tower mount, but you'll still won't have to run the wires from the shock tower to your ecu. You'll also have to wire in the knock sensor. And if your CX has a 1-wire O2 sensor, you'll have to wire in a 4-wire O2 sensor.

Edit: next time, please make just 1 thread if you have questions about a specific swap. Or at least make sure to give full information in each thread. This question here will now have a different answer than what I've given, now since I found out in your other thread that it's an OBD2 engine and would be an OBD2 B18C harness. The OBD1 and OBD2 engine harnesses have a few different plugs; distributor, alternator, and injectors. Here's is some good info on the 2 choices you have (6th post down): http://www.honda-tech.com/zerothread?id=550976 But either way you'll still have to run the wires for vtec from the passenger side shock tower mount for vtec as well as the knock sensor.