1) Don't even use anything on JWT as Base Line 2) Don't the stock ECU as a baseline 3) Rent a dyno and develope your own baseline
Watch out for JWT and Nissan getting on your back for software infringment.
The technology is there to make fuel maps and ignition maps the question is do you have the knowledge to develope an actual ignition map that is not someone else?
This sounds like a cool project just watch out for your own sake you think you have problems with your local police dept that will seem like eating ice cream on your mother lap if you get Nissan or JWT on you.