Well, we can clear it, it's been done here on our test LMM ECM, part of the 'fun' was the challenge of being able to do it.
But I sat back and thought about what could result from allowing people to do it and really no good can come from it.
If you have made a change to 'just' the speedo section to adjust for wheel sizes then you should be safe with GM as the ECM will only store that the Speedo segment was changed. It is that smart, it knows what segment was changed.
I also understand in your situation bdr2008 that you would want it cleared.
I don't want to shelve the idea of doing it, but so far the only thing I can see it doing is getting EFILive sued or GM making it 10 times harder to program these vehicles. Currently compared to other manufacturers GM have made it reasonably open for programming, they could turn that around very fast, especially using Bosch ECM's.
Have a look what the Europeans have to do to program some of the Bosch ECM's -
http://www.evc.de/en/product/ols/bdm/default.asp
Yep, remove the bottom cover every time they want to program something as the OBD-II programming system the BMW's etc use is impossible to hack. GM could always go down that path too.
We will be at SEMA this year so I am sure we will get a feel for what we should do from users and industry people...GM have a stand there right!
Cheers,
Ross