Originally Posted by HighandDry
True, you can flash back to stock, but BMW is going to be able to see how many times the car was flashed. I would think that warranty is going to be voided- correct me if I'm wrong.
There was a case of a 911 where warranty was denied because the car was previously flashed. The ECU's are probably different than BMW's, but Porsche was able to see that it was previously tuned even though it had the stock flash on it.
The technicians can not see that at the dealership, only BMW regional engineers may see that, but if they can't prove the tune is physically on the vehicle they are not legally aloud to void your warranty.