Originally Posted by username11
All that BMW would need to do is run a delta between your software revision (post tune) and a standard ECU. With the values determined through the delta, it would be easy to check for them to see if your tune has been applied. Hopefully they do this; threads like this would therefore become extinct and all would benefit.
"Hey guys, I don't like to drive fast, but I put a fake CSL bumper on my car to make it look faster, and bought a tune which does stuff to my car I have no idea about. I took it to the dealer so the dealer could inspect my ECU, I'm not sure why I did that, but here I am, can you help me?"
At the dealership level, this is not possible.
And past that level, it's unlikely for the comparison to ever take place unless there is reason to suspect foul play.
If you flashed back to stock before, it's an added layer because the map data will be back to stock.