Your KA will run with SR 370cc injectors off the stock ECU. You don't have to worry about it not starting and driving. It will just run a little rich. The NEO is a base piggy-back, but with the injectors you're using you don't have to worry too much about timing since you're not going to be able to squeeze a ton of power out of them. If it were me, I would run a bottom mount T2 manifold and use a stock nissan T28 turbine with your 370cc injectors. Then refine the fuel map with your NEO. That will net you over 200 wheel on a motor that isn't on it's last leg. If you want something way better than the NEO, return it and get NISTUNE. Then you can adjust all the parameters you want and it's almost half the cost. Since you an old AT guy, then you'll have no problem soldering in the PCB into your ECU.
So to recap (if it was MY build)
Run a bottom mount manifold with a factory T28 turbo, SR injectors (although I would prefer S15 SR injectors since they're 480cc instead of 370cc), return the NEO, buy/install nistune, drive to dyno, tune it up.