Is the B18C1 a JDM engine or is the stock wiring harness cut or damaged? If it's a USDM engine with a complete harness, stick with the B18C1 harness. Your basically just going to plug the Integra harness into the Civic's in-car harness (wth the plugs along the shock towers) and do some small wiring. You EX will already have VTEC, but you'll need to add the knock sensor wire and assuming your '93 was the same as my '92 CX, just move the wire from A20 to A17 hook up the IAB's. The stock civic EVAP wire is now the Integra's IAB wire (worked fine for me). There was a small 2 wire plug on the passagner side harness (with my '95 OBD I B18C1 USDM swap) that was the Integras EVAP wires that I ran to A20 and B1 (or any swtiched 12v source).

'96+ Integras are OBD II but the harness are the same, just some extra plugs you won't have a plug in your civic harness for and will just remain unused, you will need an OBD I ECU however. A JDM engine you will need to remove the stock JDM harness (in Japan, cars are right hand drive so the battery/steering is reversed) and run the EX harness in it's place and add the same wires (probably have to run your own IAB wire since the EX harness won't have one). I would recommend get a sheet of paper and record where the plugs go and whatnot so you don't end up frustated when you can't figure out what goes where and you already removed the GS-R harness. A digital camera will help document where everything goes too.