Knox, does your engine have a harness at all? I got the impression that it didn't. If that's the case, you'll need to find one. The ORS harness is simply an adapter they wire up according to your truck's body harness and whatever recipient harness/ecu is on the motor. I think it's also pretty important that the harness and ecu are, at bare minimum, from the same year truck- not sure if Tacoma vs 4runner matters or not but I kind of don't think so.
I also highly recommend doing the wiring yourself. It's just NOT THAT hard and you will learn a ton about your swap and save a bunch of money. There are enough resources on YT to practically hold your hand the whole way through. I am a self proclaimed electrical neophyte but after enough reading and staring at the EWD's it all came together. Mine started first try.
Also, depending on your state's emission situation, you may not even have to worry about finding a manual harness and ECU. My swap was from an auto '98 4runner and I chose to run all the auto stuff until I find a deal on a MT ecu. Haven't found one yet and it runs like a champ. I've unplugged the CEL since it's on all the time looking for the transmission. I check it periodically to see if any fresh codes have appeared and so far so good.