So I've been on here a few days collecting together the information available and I inevitably have a question.
Call it more of a query to check my progress of learning.
Am I right in saying that if I found a tuned map file for ECU xxx-xxx-xxx-J and I have orig: xxx-xxx-xxx-CG, I could run both these files through a hex editor and compare the two. When I locate strings of code that match mine these are the parts that can be adapted to tune my original file? (Assuming these matching strings are the tuned parts) Would I essentially be building myself a map for my ECU?
If you do that you will still have no idea what you did and why. You also will never learn the ecu that way, because again you don't know why the modified values are what they are. You don't know if it's the right way, or for a custom setup, or for a setup with a problem that has been "tuned around"
Start from a stock file and make the changes yourself.