Originally Posted by Singletrack
I do agree that if you tamper with the ECU, then blow your engine, all bets are off - regardless of how solid the tune might be. Of course, there have been zero cases of engine problems related to ECU tunes reported here. You can bet the farm that if someone had a problem, they would be on this site bitching. The only programing related issues I've heard of are on supercharged cars, which obviously are no longer covered under warranty by BMW.
He had his engine warranty voided by BMW because he tampered with his ECU. It's possible he had a shitty motor to begin with, but it didn't help that the ECU was reprogrammed. He's also got a few other threads up too. Sadly BMW never covered him.