I'm going to go back to a regular ignition here, at leats for awhile, just to leave out one variable in making sure it's going to run like it should (long story)...the way I made my harness (and how I do things in general) is I used a socket from another coil setup and wired from that to the coils, so that all I need to do is unplug it from the oem harness and plug that part of the oem harness into my coil and can have either one...I kept the coil on all that time, as a abckup emergency (in case my coil(s) went out), so that all I had to do was plug it back in and put the ignition wires back on or visa versa...Doing it any other way is sort of a hack job, IMO, although if you know you'll stay with COP for good, you could cut the oem harness too of course, but if you go back, you'd have to cut again and splic on the plug again; no thanks, lol.
Anyhow, I don't expect anything different going back necessarily and like I said only reason I am for now is to eliminate any variables for now (bought a miswired MAS harness that fukked up some stuff on my car, that I had to fix) until I get it dialed in, then I'll probably put the COP back on. I do recall a much smoother idle and generally running vehicle, but never got to try it under much boost (part of what the bad MAS harness did to my car).