I know this is off topic and non-helpful but I don't understand why someone would take a 75k car and mess/tune the ECU.
I used to own a MR2 turbo. I modified everything on that car including tuning the ECU to run more aggressive. Guess what? Over time the engine blew.
BMW designs these cars to be highly fast and good as they are for a 75k car. Why take a chance at ruining you perfectly fast car?
I just don't get it. Maybe I'm over that 20 something stage of my life where "mod everything" was the motto. Then again I was modding a 8k car, not a 75k piece of engineering dream.